TP 757 
. F7 

Copy 1 


The Installation of Cast Iron 
Street Mains 


WALTON FORSTALL 

PHILADELPHIA. PA. 



1913 








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©CI.A3 51850 

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CONTENTS. 


Introductory . 

Organization for Work. 

Small Towns. 

Large Cities. 

Preliminary Work.. 

Pre-inspection of Site... 

Delivery of Material. 

Nature of Equipment. 

Location of Equipment. 

Preparing for Trench. 

Removing Paving. 

Separating Material. 

Asphalt. 

Other Paving. 

Trenching. 

Preliminary Work. 

Protection pf the Public. 

Protection of the Workman. 

Protection of the Trench. 

Earth Excavation. 

Rock Excavation. 

Laying.. 

Organization for, and Details of, Pipe Laying 

Large Mains. 

Small Mains. 

Connection Work.. 

Closing Gaps. 

Cutting Pipe on Bank. 

Connecting to Existing Main. 

Inserting Branch. 

Putting on Hub Split Sleeve. 

Placing Hat Flange. 

Joints. 

Yarning.. 

Lead Joints. 

Cement Joints. 

General *. 

Material. 

Making.. 

Temperature Precautions. 

Lead Wool Joints. 

Testing Joints. 



Page 

2 

2 

2 

5 

6 
6 
7 

10 

11 
ii 
13 

13 

1 4 

16 

17 
17 
17 
20 
20 
20 

24 

25 
25 
25 
29 
31 

31 

32 

33 
35 
37 

39 

40 
40 

43 

48 

48 

50 

51 
55 

57 

58 













































IV 


Precautions Against Settlement. 

Bagging.. .. ■ 

Necessity for Bagging. 

Size of Bag Holes. 

Insertion and Witbdrawal. 

Care in Regard to Supply of Gas. 

Purging.. .;. **** 

Maintenance of Gas Supply During Main Laying 

Importance of Maintaining Supply. 

Supply by Existing Main. 

Supply by Temporary Main. 

Supply in Absence of any Main. 

Refilling.. 

General Considerations. 

Ramming. 

Puddling. 

Loose Filling. 

Cleaning Up. 

REPAVING. 

General Considerations. 

Asphalt.. 

Concrete Base Paving. 

All Other Paving. 

Recording. 

Reasons for Records. 

System of Records for New Mains. 

Field Records. 

Reports to Office. 

Permanent Records. 

System of Records for New and Existing Mains 

Small Company. 

Large Company • % . 

System of Records in Philadelphia. 

Organization. 

Field Records. 

Use of Measuring Equipment. 

Measurements : Hpw and When Taken • • 

Reports to Office. 

Permanent Records. 

Sketch Details. 


Page 

6l 

64 

64 

65 
65 
68 
72 
75 

75 

76 

77 

78 
80 

80 

81 

83 

85 

85 

, 86 
. 86 

• 87 
. 88 
. 88 

■ 89 
. 89 

■ 90 
. 90 

• 93 

• 95 

• 97 

• 97 
. 98 

. 99 

• 99 

• 100 
. 102 

• 102 

• 105 

• 105 
. 108 


Bridge Mains. 114 

Reasons for Bridge Mains... 114 

Location of Mains. 115 

Provision for Mains when Designing Bridge. 117 














































Page 

Design of Mains. 118 

Material. 118 

Joints. 118 

Rubber... 118 

• Screw. 118 

Size.. 119 

Inspection of Mains. 121 









ILLUSTRATIONS. 


Fig. Name Page 

1 Service Cart. 9 

2 Tool Box.‘. I 2 

3 Tool Wagon. 12 

4 Asphalt Screen. 14 

5 (A) Asphalt Cutter. 15 

5 (B) Asphalt Wedge. 15 

5 (C) 14-lb. Sledge for Breaking Asphalt. • . 15 

5(D) Bars for Lifting Asphalt. 15 

5(E) Curb Lever. 15 

5 (F) Iron Tunneling Bar. 15 

6 Adjustable Braces for Shoring. 19 

7 Pumps for Removing Water from Main Ditch. 21 

8 Ditch Target. 22 

9 Ditch Target. 23 

10 (A) Bar for Removing Rock. 24 

10 (B) Sledge for Removing Rock. 24 

10 (C) Frost Wedge. 24 

10 (D) Wedge for Removing Rock. 24 

10 (E) Bursting Wedge. 24 

10 (F) Caulking Hammer. 24 

10 (G) Cement Caulking Tool. 24 

10 (H) Wire Brush for Cleaning Cast Iron Pipe. 24 

10 (I) Bag Fork. 24 

10 (J) Drill used in Blasting. 24 

10 (K) Porter. 24 

12 Derrick. 27 

13 Rubber Band for Main. 44 

14 (A) Ladle for Mains i6 // and Smaller. 45 

14 (B) Pot for 16" Main. 45 

15 Tools used in Caulking.•_ 47 

16 Cement Joint. 53 

17 Air Pump. 60 

18 (A) Stopper. 67 

18 (B) Bag Pump .... 67 

19 Pressure Gauge. 7! 

20 Method of Purging Large Mains. 74 

21 Temporary Main. 78 

22 Temporary Main. 7^ 

23 Transit Book. ^ 

24 Postal Card Progress Report. 94 

25 Main Record Book. 












































VII 


Fig. Name Page 

26 Field Sketch. 101 

27 Measuring Equipment. 103 

28 Measurements at other than Right Angles. 104 

29 Progress Report. 106 

30 Sketch Record Data. 107 

31 Main Record Card . 108 

32 Designation of Curbs and Corners. 109 

33 Building and Dimension Lines. no 

34 Sketch Record Card. 112 












































{The Institute is not responsible for statements of facts or 
opinions expressed in advance papers. This paper is 
subject to revision by the Board of Directors.) 
(Copyright, 1913, by American Gas Institute.) 

THE INSTALLATION 

OF 

CAST IRON MAINS. 


WRITTEN FOR THE EIGHTH ANNUAL MEETING OF THE AMERICAN 
GAS INSTITUTE, 1913, BY WALTON EORSTALL. 

SYNOPSIS. 

This paper treats solely of the installation of cast iron bell and 
spigot mains for low pressure distribution. It does not enter into the 
principles governing the design of such a street main system, nor is 
it concerned with any questions of maintenance. It is written mainly 
with the idea of aiding the beginner to obtain a certain knowledge of 
main laying in a shorter space of time than might be possible were 
he obliged to depend on verbal instructions and daily experience. It 
begins with the proper organization for a main laying staff, and how 
their duties are affected by the size of their operations. Then follows 
an enumeration of certain preliminary work that is generally necessary 
before the trench may be opened. Excavation, both earth and rock, is 
treated in great detail from the removal of the first paving stone to 
bottoming the trench. Pipe laying includes the number of men needed 
for laying small as well as large mains, with their individual duties, 
and tells each step in the progress of a length to its final resting place. 
The various classes of main connections are described, and the con¬ 
ditions under which they are required. There is a full discussion of 
cast lead and of cement joints, with a slight reference to lead wool. 
Bagging off gas, with the precautions this entails, is thoroughly con¬ 
sidered, and the same is true of the no less important matter of purg¬ 
ing mains. The conditions under which gas supply must be maintained 
during main laying are examined and explained. Then in proper 
sequence come the different methods of refilling trenches, and the 
arguments for and against contracting for repaving. Under recording, 
the paper describes several systems of main records as applied to new 
and to existing mains, and to large and to small companies. It con¬ 
cludes with a discussion of mains on bridges under surroundings 
usually met with in cities. 




2 


INTRODUCTORY. 

The design of this paper is to describe in great detail the 
installation of street mains, including the requisite organiza¬ 
tion of the main laying force. It is meant primarily for the 
learner in distribution work, but the writer hopes that it will 
be of some assistance to older men, if only because it gathers 
in one place and in logical order, information that hitherto has 
not been thus available, concerning American distribution prac¬ 
tice. As the paper forms part of, and is taken from, a much 
larger work, it contains no reference to the designing or main¬ 
tenance of a street main system nor does it describe the equip¬ 
ment generally used. The inclusion of these subjects would 
have added too much to the existing many pages. 

It is hoped that the early appearance of the paper will be 
taken advantage of by our distribution engineers generally, and 
that they will be prepared to discuss it fully in October, so 
that when it is embodied in the proceedings, it will represent 
not merely the ideas of one man or set of men, but, as inter¬ 
preted in the light of the criticisms which undoubtedly it 
deserves, and should get, it will become a useful treatise on its 
particular detail of distribution practice. 

ORGANIZATION FOR WORK. 

SMALL TOWNS. 

The proper organization of a force for the work of main 
laying will vary according to local conditions, as the sphere of 
operation is first, in a small town, or the growing fringe of a 
large city; or second, in the congested portion of a large city. 
It will also vary somewhat in any particular locality, with the 
length and size of the main being laid, whether small, viz., 12" 
or under, or large, viz., 16" or over. (In the future, the 
words small and large will be used in this sense when referring 
to main work.) In any event, the street main work should be 
under one man who, whether the superintendent himself (as 
would be the case in many companies) or not, will be con- 


3 


sidered for our purpose as being called the general main fore¬ 
man, and will be referred to as the main foreman. 

In the first case spoken of above, viz., a small town, or the 
growing fringe of a large city, the duties of the main foreman 
will be very general. He will make a prior inspection of all 
locations where work is to be done, plan the work, decide per¬ 
haps upon the character of and arrange for the delivery of the 
specials to be used, as well as all other material, exercise a gen¬ 
eral oversight while the work is being done, and inspect the site 
after completion. In some instances, he will act as timekeeper 
and also check any reports made out by the gang foreman. 

If the work consists almost entirely of laying mains to supply 
row after row of houses, or, as they are called in Philadelphia, 
“building operations,” as the majority of these operations are 
begun in the spring and finished in the fall, and the most 
economical organization of the main force is that of a constant 
number of men, able, by working three hundred days in the 
year, to lay the miles of mains required annually, then, in order 
that the main and service work shall always be finished when 
gas is needed, or, as is more usual, when the builder is ready 
to pave street and footway, it often becomes necessary to lay a 
main in some streets soon after the house foundations are 
begun. This will sometimes mean that the proper line and 
grade stakes must be obtained from the city surveyor, and then 
the main foreman takes the gang foreman to the location and 
gives him, with reference to the stakes, all the information 
necessary in regard to opening trench. The two foremen also 
decide upon the best starting point and any other details in 
regard to the work, such as the prqper character and location 
of the necessary specials, including drips, for under the condi¬ 
tions being described, there will be few underground structures 
encountered to cause unexpected changes in plan. As 
mentioned before, the delivery of this and any other material, 
and of tools and equipment will come directly under the super¬ 
vision of the main foreman, and if the team used is also em¬ 
ployed in hauling material for service work, the main foreman 


4 


will make all his plans for this team in conjunction with the 
service foreman, in order to insure its most economical use 
each day. 

Where the recording of main work is done by the main de¬ 
partment, the main foreman will generally make the necessary 
sketches, assisted by the gang foreman for such portions of 
main as may be laid and covered up in the absence of the main 
foreman. 

To sum up, in the conditions now being described, the main 
foreman plans the movement of, and lays out in detail, the 
work of each main gang, and the gang foreman handles his 
men to get the designated work done with the greatest possible 
despatch and efficiency. 

The composition of each individual gang will depend largely 
upon local conditions. For the Philadelphia work, in the grow¬ 
ing fringe, where most of the laying is 6" in dirt streets, and 
the average job is one block, or about five hundred feet, the 
following personnel has been used to great advantage: 

1 gang foreman 

2 caulkers 

2 caulkers’ helpers 
14 laborers 

In warm weather, a water boy should be employed to enable 
the men to keep steadily at work, and not be continually 
leaving the trench to walk to the water pail, disorganizing the 
work. 

Experience has shown that with a good organization and a 
competent foreman, a small gang of this kind will turn out a 
splendid amount of work per man. Each laborer becomes a 
picked man and is worth.the extra pay he gets. It is also 
surprising, if the proper brains be directing the main work, 
how constant may be the number of laborers to take care of 
what would seem to be a very fluctuating amount of building 
operations, as measured by the number begun each month. It 
is needless to say that where a gang is continually changing 
in size throughout the year, the output per laborer is appreci¬ 
ably lessened. 


5 


LARGE CITIES. 

The second case spoken of at the beginning of this chapter, 
viz., where the sphere of work includes the congested portion 
of a large city, necessitates a change in the mode of working 
and more of an organization. The main foreman’s duties will 
be largely executive, and he can have little detail work to do, 
as he must be free at all times to go where needed. He will 
often have to confer with the official of other companies when 
changes of locations of gas mains, or other structures, are in 
question, or cases of interference, or damage, have arisen. So 
much of his time will be taken up in this way that he cannot 
have very intimate relations with the gang foremen, or lay out 
their work in detail. He must teach these foremen to be able 
to decide for themselves in ordinary cases. As he cannot 
follow any daily routine in his work, he should always keep in 
touch with his office, so that he can be reached quickly if 
necessary. 

The gang foreman it will be readily seen, should be of a 
higher type than is needed in situations where the main fore¬ 
man looks after much detail. While the main foreman will 
have direct charge of the material delivery teams, the gang 
foreman will determine the material wanted, and its time of 
delivery. These orders will usually be telephoned to the office 
for approval by the main foreman, who, because of his know¬ 
ledge as to the exact conditions of all his work, is best able to 
decide upon the details of their execution. Inasmuch as the 
careful routing of such orders as to distances traversed by 
heavy or light loads, does not appeal to the average driver, 
thp main foreman is often able, by good routing, to decrease 
considerably the work of his teams. Beside knowing how to 
handle his men efficiently, the gang foreman must possess good 
judgment, not only in ordinary routine work, as for instance, 
in regard to the amount of trench opened ahead of pipe laying, 
but also in meeting any peculiar conditions that may arise in 
the absence of the main foreman. Instant action may be 
necessary to prevent loss of life, or damage to property, and 


6 


the gang foreman should be able to act quickly and have a 
fertile mind, and ability to reason carefully. When the gang 
foreman is not stationed for the day at any one particular loca¬ 
tion, he should keep the office in touch with his movements, 
preferably by telephone. 

Neither the main foreman nor the gang foreman should be 
expected to make any sketches of the work done. To avoid 
all possible chance of misunderstanding, no job should be done 
except on a written order issued by the office and accompanied 
by a sketch giving in detail all available information necessary 
for the work. 

The personnel of each main gang will be of a fairly high 
type, especially in caulkers and helpers, because the obstruc¬ 
tions encountered and the heavy street traffic make pipe laying 
difficult. In Philadelphia a gang composed as follows is used: 

i gang foreman 
4 caulkers 
4 caulkers’ helpers 
16 laborers 

In especial cases of tedious or dangerous work, the whole gang 
should be composed of experienced men. 

For small jobs of changing mains, where backfilling follows 
immediately upon laying, such as laying around manholes, the 
gang would be as follows: 

1 gang foreman 
3 caulkers 

2 caulkers’ helpers 
i laborer 

PRELIMINARY WORK. 

PRE-INSPECTION OF SITE. 

To insure continuity of work for a main gang, it is necessary 
to have always planned out ahead, jobs covering a week or ten 
days. A pre-inspection of each street is essential to ascertain 
what obstructions may exist along the proposed line of main. 
Where a building operation is in progress, there are often piles 


7 


of building material, mortar bed, plaster bed, etc. By giving 
the builder some days’ notice of the time for beginning work, 
he will, especially if he is anxious to have the main laid, 
arrange to have a clear path for the trench. If is often neces¬ 
sary, however, to see various sub-contractors and to make 
several calls, and if possible the gang should not be shifted to 
any location until all obstacles are out of the way. 

At this point it will be well to speak about one phase of pre¬ 
liminary work in connection with large main laying, that is 
peculiar to congested conditions, viz., the ascertaining whether 
at the location given for the trench, sufficient space will be 
found. Generally, before a permit is asked for from the City, 
or perhaps before a route is laid out for the main, test holes 
have been dug to ascertain the exact location of the existing 
underground structures. The frequency of these holes and 
their extent will vary, depending upon the conditions found. 
If it is apparent that there is plenty of available space, few 
test holes will be needed. If, however, conditions are very 
congested in the route and at the location finally decided on, 
then, unless the preliminary test holes were within one hundred 
feet of each other, it is advisable at some time before actually 
beginning the work with a large gang, to open a series of test 
holes covering two or three blocks, and thus definitely deter¬ 
mine the exact location of the trench. It sometimes happens 
that this will be a zigzag line. As the work progresses, test 
holes may be opened for the rest of the route. It is always 
advisable to do this test hole work well in advance of the 
necessity for trench opening, especially if a change in location 
requires an application to the City. In length, the test hole 
should of course cover the space to be explored, and in depth, 
it should equal the probable depth of trench required. In addi¬ 
tion a bar should be driven in several feet at various points in 
the bottom of the hole to make sure that no structure lies 
beneath. 

DELIVERY OE MATERIAL. 

The delivery of material, such as pipe and specials, should 


8 


i 


also be arranged for. Where the force employed in main lay¬ 
ing is fairly constant in size for several months, it is com¬ 
paratively easy to estimate the weekly or monthly need for 
pipe. As to the yearly need, it has been found possible in 
Philadelphia to anticipate it very closely, and to place such 
orders with the foundries that carloads of pipe will be received 
as wanted, and more than 90 per cent, of the lengths hauled 
directly from the car to the street. This makes for great 
economy in handling. 

In stringing the pipe, if 12" or larger, it should be left with 
bells all pointing the same way, viz., in the direction in which 
the main will be laid. This direction should be whatever local 
conditions make most convenient, except where there is a grade 
exceeding 5 per cent., in which case the bells should always 
point up hill, reversing direction at each low point and summit. 
When the pipe is smaller than 12", it does not pay to add to 
the expense of loading and unloading by requiring one direc¬ 
tion of bells. The pipe should be strung as closely as possible 
to the curb and on the side of the future trench, except in the 
case of large pipe when the trench is some distance from the 
curb, and the excavated material will occupy all the space 
between curb and trench, so that the pipe must be rolled across 
the street as needed. Under ordinary city conditions, where 
the street is open to travel, the pipe must be properly lamped 
each night. 

In addition to the pipe, certain special castings may be 
delivered on the street prior to beginning work. This is more 
apt to happen with large mains than small ones, for in the 
former case, there are often opportunities to economize by 
hauling the specials directly from the car, while the small 
specials, being ordered in large quantities, usually before the 
beginning of active main laying, are at the various store yards. 
Also, a large main job implies, as a rule, a length of one 
thousand feet or more, and the use of a minimum number of 
certain specials no matter what may be the underground condi¬ 
tions. This is not true of the average 6" job under Philadel- 


9 


phia conditions, where, if laying from an intersection already 
in place, to the other end of a block, beyond which the develop¬ 
ment is uncertain, there may be no specials of any kind re¬ 
quired. Again, if an intersection is to be laid, it may be known 
what tees and crosses are required, but the necessity for bends 
is uncertain, depending entirely on underground conditions, yet 
to be revealed. Therefore, it may frequently be more 
economical to deliver no specials until the exact needs of the 
job are known. 



Fig. i.—Service Cart. Page io. 

Concerning miscellaneous equipment, such as blocking, 
cement, lead, etc., it is a mistake to have on the street any 
more than is necessary to furnish economical hauling condi¬ 
tions from the store yard. Every pound of material left over 
on a job, to be transferred to the next site, involves unneces¬ 
sary hauling expenses. Where cement is used, the more that is 
kept on hand, the more chance of spoiling from storms. One 
method of caring for small lots on the average job, where a 
shelter shed is not justified, is to pile the cement bags on the 
wooden blocks, high enough to avoid possible wetting, and 
then cover over with a water tight canvas. 


2 





10 


NATURE OF EQUIPMENT. 

The normal equipment for a main laying force depends, first, 
on its size, second, on the character of the main work, includ¬ 
ing the kind of jointing material used, and third, on conditions 
of paving and weather (winter or summer). The equipment 
listed below can be carried in the service cart (Fig. i), and 
will suffice for the force described on page io when laying 4", 
6" or 8" pipe. For larger mains, additional equipment will be 
necessary. 


1 Asphyxiation kit 

2 Bags, 4", 6 " and 8 " 

1 Bar, leak 

1 Bar, rock pinch 

1 Bar, search 

2 Bars, tunneling 

1 Brush, pipe, 4", 6 " and 8" 

1 Bucket, galvanized iron 
6 Chisels, cape 
6 Chisels, dog 
8 Crowbars 

1 Cup, drinking 
13 Cutters, asphalt 
12 Diamond points 

Fittings and nipples, assort¬ 
ment 

2 Forks, bag 

1 Gauge, syphon U 

2 Hammers, 14-lb. sledge 
1 Hand saw, crosscut 

10 Lanterns, red 
10 Lantern rods (unless danger 
signs are used) 

1 Level, small pocket 
i Level, 24" 

300' Line, ditch 
1 Mattock 
1 Oil can, squirt 
15 Picks 
15 Pick handles 
5 Pins, ditch line 

For Cement Joints. 

1 Board, mixing 
1 bag Cement 

3 prs. Gloves, rubber 
1 Sieve, cement, 12" 

1 Trowel 


1 Pipe, smelling 

1 pair Pliers, gas 

2 Porters 

2 Plugs, wooden, 4", 6" and 8" 
1 Pump, bag 

5 Rammers 

6 Rods, canvas screen 

1 6' Rule 

3 Screens, canvas 

2 Shovels, flat nose, “D” handle 
13 Shovels, sharp nose, “D” 

handle 

1 Shovel, sharp nose, straight 

handle 

15 Signs, danger 
Soap and brush 

2 Stoppers, 4", 6" and 8" 
Tallowcloth 

1 50' Tape, canvas 

1 Tapping machine, combina¬ 

tion, with drills 

2 Targets, ditch (either type) 

3 sets of Tools, caulking 

2 Wedges, asphalt 
6 Wedges, concrete 
6 Wedges, frost 

3 Wedges, pipe bursting 

1 Wrench, plug 

2 Wrenches, Trimo, 14" 

10 lbs. Yarn 


For Lead Joints. 

3 Bands, pouring, 4", 6" and 8" 
1 Bellows 
1 Furnace, lead 
1 Ladle, pouring 
25 lbs. Lead 


II 


LOCATION OF EQUIPMENT. 

When pre-inspecting the site, the location of such equipment 
as tool boxes (Fig. 2), tool wagons (Fig. 3), service carts 
(Fig. 1), etc., is usually determined. When there is much 
equipment a vacant lot is, of course, preferable to a roadway 
location. A footway location should be avoided, unless it is 
wide and little travelled. Ordinarily, an available and suitable 
location is in the roadway of an intersecting street at an end 
of a one-block job, or near the center of a larger job. 

PREPARING FOR TRENCH. 

The occasional necessity for line and grade stakes has been 
previously mentioned. It is always well to give the surveyor 
at least a week’s notice. When there are no curbs at either 
side of the street, or at the intersections, stakes are needed. 
If either side, or intersection, has curb set, by obtaining from 
the surveyor the width of street, whether straight grade 
through the block, and if not straight grade, the location and 
height of the summit, then by means of tape line, level board, 
tees and targets, the height of curb, and therefore proper depth 
of trench can be determined accurately enough for most jobs. 

The trench is marked out for the width required for the size 
of pipe being laid, the schedule in use in Philadelphia being as 
follows: 

Size.... 6" 8" 12" 16" 20" 24" 30" 

Width.. 18" 18" 18" 22" 26" 30" 36" 42" 

If the street is paved, both sides of the trench are marked 
with colored crayon, yellow or red preferably. One way of 
doing this is to locate each side of the trench from the curb 
every one hundred feet, and then stretch a line between each 
series of points, first on one side of the trench, arid then on 
the other, marking along the stretched line. If there is no 
paving, a guide along one side of the trench usually suffices, 
being given by a rut marked by pick or shovel from a 
stretched line, or else the line may be left in place on the side 
opposite to which the excavated material is placed. 




Page ii. 


Fig. 3.—Tool Wagon 

















i3 


The pipe is also lined up on the opposite side of the trench to 
the proposed location of most of the excavated material. This 
ordinarily means that it will be on the side nearest the curb. 
In lining up, the bells should be pointed in the proper direction, 
and the pipe should overlap as nearly as possible the exact 
depth of joint. This will obviate any necessity for shifting 
pipe lengthways along the trench. Of course, the larger the 
pipe and the longer the stretch lined at any one time, the more 
will be the possible saving by careful lining. Where the lining 
covers the entire job, any shortage or excess of pipe will be¬ 
come evident at once. Where on large mains, the earth is 
thrown on the curb side, and the pipe strung across the street, 
it may not be advisable to line the pipe, but simply to roll it 
across as needed. 

REMOVING PAVING 

t 

SEPARATING MATERIAL. 

On a paved street there are usually several classes of 
materials to be removed from the trench, and each class should, 
if possible, be kept more or less separated. Asphalt pieces, or 
paving blocks, are generally piled, often forming a retaining 
wall for any large quantity of earth excavation. Bricks or 
rectangular stone blocks are often of use in making channels 
for conducting water flow under excavated material. Sand or 
concrete is kept free from any contact with earth. 

In the ordinary case of a small main, the earth would be 
thrown on one side, and the paving material and base on the 
other, and the latter might be allowed to lay where it fell, not 
being in sufficient quantity to interfere with laying operations. 
Occasionally a streak of gravel, or sand, is encountered, and 
if it is of value for repaving or for other use, care is taken to 
keep it separate from the material. Where there is a loose 
or solid rock, the pieces are generally thrown clear of the 
earth excavation, so they will not be covered over and can 
easily be hauled away. 


14 


asphalt. 

In cutting asphalt, the asphalt screen, Fig. 4, should always 
be used where there is any danger of injury to property or 
persons from flying chips. As a rule only one side need be 
screened, viz., that towards the footway—but if the trench is 
near a car track with much traffic, and open cars are in use, 
the track side will need a screen. Support for the screen is 
obtained by the device shown, and sometimes by tying to trees 
or poles. 



Fig. 4.—Asphalt Screen. Page 14. 

Each cut is made by two men working together, using asphalt 
cutter A, Fig. 5, one cutting right, the other left, and the line 
marking the side of the trench, forming the center of the cut. 
Each pair of cutters are spaced eight feet apart, the first pair 
cutting the right hand line, and the second the left hand line, 
etc. This staggering of the cutting work enables the whole 
gang to be closer together, and, therefore, under better super¬ 
vision by the foreman. With a gang of not more than twenty 
men, it is advisable to place at work cutting, all the men that 
tools or space will allow, and finish this work quickly. In any 







i5 


case, after all the cutting is finished, one man is given a regu¬ 
lation street broom and sweeps up all the chips, both those 
inside the screen, and any that may have passed over the screen 
and lodged on footway or roadway. 

If the asphalt is on a concrete base, with both sides cut 



F ig. c_(A) Asphalt Cutter, page 14. (B) Asphalt Wedge page 16. 

(C) 14-lb. Sledge for Breaking Asphalt, page 16. (D) Bars for Lifting 

Asphalt, pages 15 and 16. (K) Curb Lever, page 16. (F) Iron Tun¬ 

nelling Bar, page 17. 


through to the base, the asphalt can be lifted off with bars, D, 
Fig. 5, each lifting gang being composed of four men, viz., 
two men using the bars, one breaking the asphalt to pieces 








i6 

with a 14-pound sledge, C, Fig. 5, and one man carrying away 
the pieces. As many gangs may be set to work as the width 
or length of trench will allow room for. 

If the base is a rock or bituminous one, the asphalt is re¬ 
moved as follows: Asphalt wedges, B, Fig. 5, are driven in 
at the bottom of the cut towards the center of the trench, at 
an angle of 45 0 with the paving. Four wedges, all on one side, 
spaced about twelve to fifteen inches apart, are used at one 
time, driven in for at least six inches, and then loosened by 
hitting down on the upward turned face of the wedge. At 
the same time the asphalt is sledged on top at about the centre 
of the trench. Then the wedges are withdrawn, bars placed 
in the holes thus left, and the asphalt raised. With the width 
of trench as opened for small pipe, all the asphalt can ordinarily 
be thus raised from one side. If not, or on wider trenches, the 
same procedure of wedging and sledging must be followed on 
the other side of the trench. It is often advisable to begin to 
wedge up another section of asphalt before raising all the 
asphalt that has been loosened. By leaving in the last wedge, 
a better purchase is obtained on the next section. The gang is 
composed of six men, three handling the sledges and wedges, 
one alternating between the bar and the sledge, and two remov¬ 
ing the asphalt pieces. At times the three using the sledges 
will aid on the bar in prying up the asphalt. 

On a bituminous base, where the distance between cuts is 
over thirty inches, the regular curb lever, E, Fig. 5, may often 
be used to better advantage than the regular bar, D, Fig. 5, in 
lifting the asphalt after it has been loosened by wedges and 
sledges. 

The asphalt once loosened, is broken up with sledges to a 
one-man size and piled preferably on the footway along the 
curb, in heaps about two feet by four feet by three feet high, 
with centre twelve feet apart. 

OTHER PAVING. 

Where there is vitrified brick, belgian block, asphalt block, 
rubble, cobble, or macadam paving, instead of marking the sides 


of the trench by crayon, as before described, an ajternative 
method is to drive in ditch line pins at points one hundred feet 
apart. Enough paving is removed to make room for the pins, 
which are driven in at an angle of 45 ° into the paving, pointing 
out from the centre of the trench until the head of the pin is 
almost flush with the paving. In this way the pins will not 
become loose as excavation proceeds. A line is stretched from 
pin to pin, and forms the guide ‘for paving removal and for 
excavating. 

For vitrified brick, belgian block and asphalt block, the 
removing gang is composed of one man barring out paving 
with the all iron tunneling bar, F, Fig. 5, one man standing in 
the trench, lifting the paving and throwing it towards the curb, 
and one man at the curb piling the paving material. For these 
classes of paving, and also asphalt, it is always best to remove 
paving by a special gang, and keep this work well ahead of the 
trenching, in order to avoid using the trenching force on re-‘ 
moving paving. 

For rubble, cobble or macadam, the trench is laid out in 
twelve foot sections, and each man removes his own paving 
with pick and shovel, throwing it off to one side of the trench, 
any additional moving and piling being done by separate men. 

TRENCHING. 

PRELIMINARY WORK. 

PROTECTION OF THE PUBLIC. 

Preliminary to, and also coincident with, the opening of any 
trench, certain precautions are necessary for the protection of 
the public, of the workman in the trench, and of the latter 
itself. Local conditions will determine in each instance just 
how many of- these precautions are required. 

Traffic, both roadway and footway across the trench, may 
have to be provided for. A footway bridge in its simplest 
form will be one or two planks laid across the trench, battened 
together, and with a plank on each side to act as a guard. 


i8 


This will serve where the traffic is light and the job is of a 
few days duration. In laying large pipe, or long lines of small 
pipe, where important streets are opened, the footway bridges 
should be at least three feet wide and have sides three to four 
feet high. These bridges are moved from point to point as 
the work progresses, and six may suffice for even the largest 
job. No matter what form of bridge is used, attention must 
be paid to each end to prevent it becoming a cause of stumbling. 
Earth placed at the end will remove this danger and also hold 
the bridge in place. 

Roadway bridges should be made from 3" planking. Cross¬ 
pieces are placed across the trench about two feet apart, pro- • 
jecting fully two feet into each bank. Planks, parallel to the 
trench, laid on the cross pieces, form the floor of the bridge, 
which should not be less than eight feet wide, as measured 
between the guard railing put up across each end. The floor 
*of this bridge should, as far as is possible, be level with the 
top of the street. Care should be exercised in making a good 
joint with the street surface at each approach to the bridge, 
and earth may be used to good advantage in this, especially 
where the bridge is somewhat above the paving. 

Any trench for large pipe, or a trench for small pipe parallel¬ 
ing a car track, the excavated material in each case being on 
the curb side, should have a proper guard rail placed along the 
exposed side. This can be made by laying three or four pieces 
of 6" x 6", or 8" x 8", along the trench, about twelve feet apart 
centre to centre. To each piece a 1 " x 6", three feet long is 
nailed as a post, and a 1" x 3", or 1" x 4" nailed to the top of 
these posts, forms a top rail. This rail is, of course, fairly 
flimsy and will need bracing at intervals. 

In excavating under car tracks, any paving between the 
tracks, and for the space of one foot outside each rail, should 
first be removed and then 3" plank laid in this space across the 
trench parallel to the rails, and projecting two feet into the 
bank on each side of the proposed trench. These planks should 


i9 


be flush with the rail and well secured by driving earth in tight 
at both ends of each plank, after it is in position. 

In the provision of bridges, as well as in any other steps 
necessary to minimize the inconvenience to the public, caused 
by main work, niggardliness, is apt to be poor policy, and a 
proper appreciation and provision for the rights of the public 
is quite compatible with efficient and economical operation. 



Fig. 6 .—Adjustable Braces for Shoring. Page 20. 


The exact requirement as to free access to fire hydrants will 
probably vary in different places. Certainly excavated material 
should be kept at least six feet from a hydrant, and access to 
it both night and day provided, even if this means a bridge 
across the trench. 

At night the trench and all material should be protected by 
danger lanterns. 






20 


PROTECTION OF THE WORKMAN. 

The principal source of danger to a trench worker, viz., a 
cave-in, is generally absent in gas main work, because of the 
shallow trenches usually sufficing. If, however, because of 
deep excavations or unstable material, (as when the trench 
lies close alongside of a former trench), there is any question 
of the stability of the trench sides, the matter of shoring should 
receive careful attention. Usually a stretcher of 2' x 12", 
sixteen feet long in one or two lines, held apart by adjustable 
braces, Fig. 6, will suffice. Where sheet piling is required, 
1" x 12" boards may be placed back of two lines of stretchers. 
Naturally, where shoring is resorted to, undue weight should 
be kept from the trench side, and this may mean in some cases 
a second handling of material to keep it back from the edge of 
the opening. 

PROTECTION OF THE TRENCH. 

Provision should be made to prevent any surface drainage 
flowing into the trench. Often such drainage must be con¬ 
ducted under the excavated material. At other times damming 
will suffice to divert surface flow away from the trench. There 
is no duty of the gang foreman more important than to have 
his trench protected from the results of violent rain storms. 
Where underground water is flowing into the trench, a pimp 
hole should be made, and a pump of either type in Fig. 7 
placed in. position. In most soils, the presence of water will 
be very disastrous to the trench sides, so the water must be 
kept down. 

Under this head may be considered the necessity for marking 
at the trench side; the probable location of any water services 
crossing the trench. In each case the proper laborer should be 
shown the mark, and be cautioned to be on the lookout for the 
service when approaching the proper depth, in order to avoid 
any chance of injuring it. 

EARTH EXCAVATION. 

For small mains, the ditch line and pins mark the side of 
the trench opposite to the excavated material. Each man 


21 


measures off with his shovel a space of twelve feet, and is 
assigned this space for his work. This sectioning of the work 
affords an easy way of comparing the relative efficiency of each 
laborer. In each gang, it is advisable to have one or two men 
better paid than the rest and expected to serve as pacemakers. 



Pig, 7 .—Pumps for Removing Water from Main Ditch. Page 20. 

If conditions are alike along the trench, the gang foreman ex¬ 
pects all the sections to go down equally fast, and, in practice 
this pitting of each man against his fellows conduces to high 
efficiency. The men take more or less pride in finishing first, 
and the laggards are teased. 

For large mains, both sides of the trench are marked by a 










22 


line. For mains up to 16" inclusive, the diggers are expected 
to throw the material far enough to render unnecessary any 
subsequent trimming. For 16" mains, the diggers are placed 
twelve feet apart, for 20" and 24", eight feet apart, and for 



Fig. 8.—Ditch Target. Page 23. 

30", six feet apart. For 20" and 24", no trimming is done 
until the excavation has been completed. For 30", at a depth 
of four feet, it is necessary to place one man on the bank to 
trim the material thrown out by every two diggers. 















23 


On every job, special men, such as caulkers, or pipe layers, 
are assigned to open over the mains to which connection will 
be made, and over any places where obstructions are expected, 
the places above described, being those which may disclose 
conditions affecting the depth of the trench, and which there¬ 
fore must be known before any bottoming can be done. 



Fig. 9.—Ditch Target. Page 23. 


The considerations affecting the depth of a main do not fall 
within the scope of this paper. It suffices here to say that a 
cover of three feet may be regarded as standard. 

After the depth of trench has been decided, the ditch targets, 
Fig. 8 or Fig. 9, are placed in position. 

When working in frozen ground, one or more holes should 













24 


be made through the frost, and then by using the frost wedges, 
C, Fig. io, and barring off from the face thus made, the frozen 
ground can be lifted off much as would be a concrete base. 

ROCK EXCAVATION. 

Where blasting is not necessary, as the rock may be removed 
by bars, A, Fig. io, wedges, D, Fig. io, and sledges, B, Fig. io, 
the men work in pairs in a section so as to give each other 
assistance. The small spalls are thrown with the dirt on the 
opposite side of the trench from the large stone. 



Fig. io. —(A) Bar for Removing Rock, page 24. (B) Sledge for Remov¬ 
ing Rock, page 24. (C) Frost Wedge, page 24. (D) Wedge for Re¬ 
moving Rock, page 24. (E) Bursting Wedge, page 36. (F) Caulking 

Hammer, page 52. (G) Cement Caulking Tool, page 52! (H)Wire 

Brush for Cleaning Cast Iron Pipe, page 26. (I) Bag Fork, page 66. 

(J) Drill Used in Blasting, page 24. (K) Porter, page 30. 

Where blasting is required, three men form a gang, and the 
gangs work as close together as possible. One man holds the 
drill, J, Fig. 10, and two men strike. The charging, covering 
and firing of the holes should be delegated to one man, who 
should be an experienced rock man. Upon this man’s judg¬ 
ment will depend the placing of the holes and the charge used. 
In general, the attempt is always to secure a face extending the 
full depth of the proposed trench. By staggering the holes in 
the various rows, the best progress is made. Where the rock 















25 


is very hard on small mains, it is advisable to start with a 
width of trench twice that required for earth. This will allow 
for failure to blow out to complete width in places. Often, of 
course, the trench will widen still more from blowing. 

All firing should be done from a battery. Great care must 
be taken to be sure that all workmen and the public are at a 
safe distance before firing. 

There should be a space of at least 4" between any solid 
ro.ck left in the trench and the nearest point of the main as it 
rests on its blocking. This is necessary to minimize the chance 
of future breaks, or leaks, due to later blasting operations when 
laying other structures. 


LAYING. 

ORGANIZATION FOR, AND DETAILS OF, PIPE 
LAYING. 

LARGE MAINS. 

The trench having been excavated, as previously described, 
is now ready for the pipe laying gang. Before telling of their 
work, the complete organization for laying 20" and larger 
mains will be here given as follows: 

One trenching foreman and eighteen men 
One laying foreman and twelve men 
One back-filling foreman and eight men 

Better results are obtained by having one foreman over every 
separate gang, than are possible by attempting to work with 
only one foreman. If the general main foreman is not on the 
work'frequently, authority in his absence should rest in one of 
the foremen, probably the laying foreman. The laying gang, 
if working steadily, would require more diggers and backfillers, 
but in practice, obstacles arise to interfere with laying, and 
therefore the laying gang is always used more or less to aid 
the other gangs. 

The laying gang contains four caulkers, or joint makers, 
and eight pipe-men. As far as possible, the various routine 
3 


26 


duties that arise should be definitely assigned, to individual 
men, so that as the work progresses there is no confusion and 
each man becomes adept at his special lines of work. The 
foreman lays out the bell holes and starts his gang on them, 
also borrowing laborers from the trenching gang if necessary. 
Each bell hole extends from three feet in front of, to one foot 
back of the bell, clear across the bottom of the trench. Its 
bottom is four inches below the regular trench bottom, and its 
width, as measured along its bottom, is twenty inches greater 
than the trench width, tapering off to, and reaching, the trench 
width, fifteen inches above the proposed location of the pipe 
top. The material thrown out from the bell holes should be 
trimmed back, and there should be a two foot passage-way on 
the street on each side of the trench, before laying starts. 

A dozen or more bell holes being completed, blocking is 
placed in position on the trench bottom. The “back” block is 
put with its near edge one foot back of the face of the bell, 
while the “front” block lies with its near edge three feet in 
front of the face of the bell. Back-filling will be reduced and 
the cavity under the centre of the pipe lessened if the trench 
has been so dug that the blocks may be set in the trench bottom 
so their tops will not clear it much more than one inch. This 
condition is difficult to obtain, however, and where there is 
insetting, care is necessary to ensure that the block rests on a 
flat surface, and not a concave one. The back blocks are set 
by spanning from one set to another with a level board set for 
the determined grade of the main. Or, each back block may 
be set by using a target. The front block is always set a little 
lower than the back block so that the main will just clear it. 

The pipe which has been previously cleaned on the inside, 
and all dirt and scale carefully removed from the inside of the 
bell and the outside of the spigot end by a wire brush, H, Fig. 
io, is rolled in position on the skids spanning the trench. The 
derrick, Fig. 12 is so placed that it will lower the pipe into the 
position desired. When moving the derrick, one man is at 
each of the rear legs and two men at each of the front legs. 


27 


(The front side is considered as the side on which the winch is 
located.) When in position and in use, the four men on the 



Fig. 12.- Derrick. Page 26. 

front side remain, but the two men at the rear legs are avail¬ 
able for other work. The sling is adjusted so that the spigot 









28 


end will be slightly heavier than the bell. The pipe is raised 
until the bell end clears the front skid, which is removed by the 
proper man while another man bears his weight on the bell, 
thus causing the spigot end to clear the rear skid. This in 
turn is removed and the pipe lowered. If, because of 
obstruction, the pipe cannot be lowered at the point where it 
is to be laid, then, it must be moved along the bottom of the 
trench by successive shifting of the derrick, or if the use of 
the derrick is not possible, the pipe is lowered upon a timber 
truck and rolled into position over a board platform laid on the 
trench bottom. 

While the pipe is being lowered, there are two pipe men in 
the trench, one in front of the bell end of the length being 
lowered, and one just back of bell end of the last length laid, 
into which he guides the spigot end of the descending length, 
aided by the other man, who grasps its bell end. When the 
bell of the descending length is from a foot to eighteen inches 
above the blocking, and its spigot end has entered the bell end 
of the last length laid, the man on the derrick brake releases 
the latter and the length falls free. This causes it to strike the 
blocking with sufficient force to firmly bed the latter. The 
length is once more raised by the derrick to just clear the 
blocking, and is then pushed home with a bar by the man at its 
bell end. The foreman in the meantime has gotten into posi¬ 
tion to sight along the line, and if the length is in line, he 
gives the signal to lower. If not, he indicates the shifting 
required before lowering. 

The length is prevented from getting out of line by the inser¬ 
tion of blocks and wedges between the pipe and each side of 
the trench, several feet back of the bell. These blocks are not 
removed until the earth has been refilled around the pipe along 
four or five feet at the centre of the length. In the case of 
cement joints, this refilling is always done before the joint is 
made, but in the case of lead joints, such partial refilling need 
not be done. Where the trench is at all unstable, this refilling 
is of great importance. 


29 


While this blocking is being done, the men who removed the 
skids have placed them across the trench, in the proper posi¬ 
tion for the next length, and rolled this length upon the skids 
in position for lowering, and are ready to assist in moving the 
derrick to the new position. From this point, the sequence of 
operations already described, is repeated. 

As soon as the length is wedged in position, two caulkers 
start to drive in wedges on the front block, viz., the one under 
the spigot end of the length just laid, and raise this spigot end 
until it is central in the bell end of the length last laid. The 
joint is then yarned. At this time, wedges may be driven on 
the back block, care being taken not to raise the length off this 
block. 

In laying pipe, it is often necessary to remove shoring. This 
work is done by the pipe laying gang, and may require the 
especial attention of the foreman to prevent too many shores 
being out at any one time, or too great delay in replacing 
shores, for carelessness in these matters may involve damage 
to both work and workmen. 

SMALL MAINS. 

For small mains, under the ordinary city conditions, where 
each job is only one or two blocks in length, the entire main 
gang will not exceed eighteen men, and will include two 
caulkers and four pipe men. 

After the trench has been completed, or nearly so, and any 
special work of connecting to existing mains finished, the 
caulkers and pipe men are started on the bell holes. Each 
bell hole should extend from eighteen inches in front of the 
bell to the back of the bell, should have a clearance of six 
inches under the pipe and of fifteen inches on each side. Back 
of the bell hole, a notch is cut in the bottom of the trench for 
the block, but care is taken to make the top of the block slightly 
above the trench surface. 

While the pipe is being laid, two men are in the trench, one 
a caulker with a spirit level and a bundle of yarn strips, cut to 
the proper length, at the spigot end of the length to be laid, and 


30 


the other a pipe man with a porter, K, Fig. io, at the bell end. 
Three pipe-men are on the bank, and one inserts a porter in 
the spigot end of the length as it lies along side the trench, and 
lifts it. As it raises, a pipe man slides over the spigot end a 
loop of rope already made and resting against the end. He 
holds one end of the rope and passes the other end to a pipe 
man on the other side of the trench. The two^men take up the 
slack on the rope, and then the man who raised the spigot end 
with the porter, goes to the bell end and pushes it off into the 
trench. The men holding the rope attached to the spigot end, 
prevent that end from dropping all the way to the bottom. The 
two ends of the rope are then taken by one of the two men, and 
he straddles the trench, while the man in the trench at the bell 
end raises this end with his porter. The length is thus 
suspended only a few T inches above the trench bottom. The 
spigot end is caught by the caulker in the trench, who wraps 
a piece of yarn around it and enters' it into the bell end of the 
length last laid. Is is then pushed home by the man at the bell 
end. Now one end of the rope is dropped, and after entering 
the spigot end, the caulker pulls the rope from around the pipe 
and walks to the bell end. Here he places his level on the 
pipe to see whether there is the proper fall. If not, the proper 
level is obtained by varying the blocking, the pipe being raised 
by the pipe man in the trench, and the caulker inserting the 
block which is handed to him by the pipe man on the bank, 
who had held the rope. 

In the meantime, the other two pipe men on the bank have 
gotten another length into position for lowering, with the rope 
under it, as described before. The second caulker is follow¬ 
ing along, driving in the yarn put in by the first caulker. When 
all the pipe has been laid, or when it is desired to begin 
making joints, the foreman straddles the trench at one end of 
the line, and lines up the length by the aid of two pipe men who 
walk along in the trench, each with a long bar, one on each 
side of the pipe. 

The procedure above described will care for mains as large 


3i 


as 8". For 12" there is needed two more pipe men and another 
rope to be used at the bell end over a porter inserted in the 
bell. The rope at the spigot end will always require two men. 

There will be instances where 16" pipe may be laid without 
a derrick, and in that case it will be treated just as 12" with the 
addition of two more men to the pipe laying gang. 

CONNECTION WORK. 

CLOSING GAPS. 

The procedure followed in straight pipe laying has been 
pretty well covered, but some other necessary phases of main 
laying are still to be described. Every main laid is connected 
at one or both ends to existing mains, and often neither con¬ 
nection is made until the close of the work, and involves, 
therefore, the closing of a gap. Where 8" and smaller, this 
connection can be made by “folding in” instead of sleeving, 
if the trench is free enough of construction to permit what¬ 
ever deflection from a straight line is required for the “fold.” 
As far as possible, it should be known before laying is 
begun, in what way connection will be made to the existing 
main. If by folding, then a gap two inches more than the lay¬ 
ing distance of two lengths should be left. * This will make the 
folding a little easier, and by distributing the two inches over 
the three joints making up the fold, no one joint will be very 
far from home. In folding, the far ends of the two lengths 
forming the fold, are put home in the ends of the lines to be 
connected, and then the adjacent ends of the folding lengths 
raised by ropes, until spigot will enter bell, when they are 
lowered into line, and the joints, if necessary, equalized, as 
indicated by each of the bells concerned in the “fold,” being 
equally far from the line marked on its engaging spigot. This 
line shows where the bell should come if the spigot is home, 
and should be marked on every spigot forming part of a fold, 
where there is over half an inch slack to be taken up per joint. 

For pipe, 12" and larger, the use of a sleeve is usually prefer¬ 
able to folding. Much time has been lost through attempts to 
fold large pipe, in order to avoid the fancied disadvantages of 


32 


a sleeve and to save one joint, and often all the time spent was 
lost and the sleeve resorted to after all, especially if the fore¬ 
man tried to work without any slack. The use of a sleeve will 
enable a spigot piece to be used, and in large work, where a 
stock of old spigot pieces may be on hand, the gap left should 
be of the right length to use up one of these pieces without 
further cutting. Where a pipe must be cut for the gap, its 
length should be at least one inch less than the distance between 
the face of the bell and the end of the spigot to be joined. This 
is especially important ih very large pipe where the cut may 
break out a little jagged, and where an attempt to make a 
cut piece just the distance between bell and spigot, is apt to 
result in a piece too long at various points, necessitating a 
tedious cutting off of these projections. Naturally, in using 
the cut piece, the more uneven end is put into the sleeve. Be¬ 
fore the cut piece is lowered into the trench, the sleeve is 
placed over the spigot end of the gap, and on this end and also 
on the end of the cut piece to go in the sleeve, a line is marked 
seven inches back from the end. Then the cut piece is lowered 
and put home in the bell, the sleeve is slipped forward over the 
gap and placed so that each face is equidistant from the marked 
lines. Such a sleeve joint involves an air gap of at least an 
inch longer than the bell depth. Unless the sleeve used is 
provided with internal ridges to serve as a joint backing, this 
gap should be covered by sheet metal to prevent any chance of 
the yarn and lead, or cement, from either sleeve joint finding 
their way into the pipe. 

CUTTING PIPE ON BANK. 

The procedure in cutting pipe on the bank is as follows: 
The proper length is marked off from either end of the pipe 
at four points at least. If the measurement is made from a 
bell end, the necessary allowance must be made for the bell 
depth. The pipe is then rolled until a line has been drawn, 
completely around it, through the marked points. Before 
cutting begins, it is placed on skids, one under the end 
farthest from the cut, and the other under the cut, and care 


33 


taken to see that it stays there. No support at all should 
be placed under the short end. The skids should be as 
solidly placed, and as nearly level, as possible, in order that the 
pipe will not jar out of position during cutting. Each skid 
should be long enough to allow at least one and one-half 
revolutions of the pipe. For pipe, 12" and smaller, one man 
holds a dog chisel, one strikes with a fourteen pound sledge, or 
ten pound striking hammer, and a third rolls the pipe. For 
larger pipe, there are two men striking, and a man at each end 
of the pipe rolling it and keeping it in proper position. In 
every case, a continuous cut is made around the pipe, and is a 
comparatively light cut, not more than y$" deep. On the com¬ 
pletion of this first cut, the cutting continues around the pipe 
as many times as may be necessary until the pipe breaks. With 
proper care, a clean cut will always be made. If for any 
reason the pipe breaks off irregularly, and the result is one or 
more places two inches shorter than desired, another cut will 
probably be required, unless the irregular end can form part 
of a deep sleeve joint. Any projection beyond the desired line 
can be cut off, but comparatively light blows must be used, to 
prevent cracking back of the line. 

CONNECTING TO EXISTING MAIN. 

At times the new main will be connected at the start to the 
existing system, and laying proceed without leaving any gap, 
gas being kept back by bagging. In such a case, it is, of 
course, imperative to do the connecting first. When a gap 
is left, however, the connection and any necessary alteration 
to the existing main need not be done at once, and as such 
alteration is usually harder than straight pipe laying, some 
foremen have a bad habit of putting it off till the end of the 
job. As a rule, expense will be saved by doing all the work 
necessary to close the gap except the actual closure, early in 
the job. It has already been noted under “Trenching,” what 
an influence the connection to the existing main has on the 
bottoming of the trench. 

In connecting to existing mains, the Philadelphia schedule 
is as follows: 




34 


t/3 

£ 

o 

►H 

u 

w 

£ 

o 

a 


< 

o 

w 

D 

Q 

W 

« 

CJ 

03 


a: 


cd 


be 


‘K 

w 


<L> 

s: 

00 


rr 

¥+ 
• w* 

cd 

s 

St 

<u 

£ 


V 

X 

33 


2 " 

Insert 

Branch 

- - 

3 " 

Insert 

Branch 

- ~ 

4 " 

Insert 

Branch 


6" 

Insert 

Branch 

- 

8" 

Insert 

Branch 

« 

12" 

Insert 

Branch 


16" 

Insert 

Branch 

• 

20" 

Hub 

Sleeve 

4 4 

4 4 

4 4 

Insert 

Branch 

4 4 

4 4 

24' 

Hat 

Flange 

H 

4 4 

4 4 

Insert 

Branch 

4 4 

4 4 

4 « 

<D 

. ^ 5 P 

V « H 

4 4 

4 4 

4 4 

Insert 

Branch 

4 4 

4 4 

4 4 

4 4 


V V V 

V V V 

Tf VsO CO 


V 

\ 


V 

V 


CN vO 


V 

V 

O 

<N 


v v 

V V 

O 

CN CO 


























































35 


As is seen, the idea is to use a hat flange wherever the disparity 
between the connecting mains is very great, and the largest so 
large that a hub sleeve would involve heavy cost. As the 
disparity and the size of the largest main decrease, hub sleeves 
are used, and the ordinary branches. It is not always possible 
to follow the schedule strictly. Occasions arise where local 
conditions force the use of a hat flange, or hub sleeve, because 
of no room to insert a branch. 

inserting branch. 

In mains below 12". the insertion of a branch is not attended 
with any special difficulties, but with large mains, the work 
requires considerable care, chiefly in regard to the cutting of 
the pipe and the bagging off of gas flow. The insertion of a 
branch will here be described without, however, any detailed 
description of bagging, as this will be taken up further on. 

The location of the branch being determined, a sufficient 
length of the existing main is uncovered to afford room for 
bag holes on either side of the proposed cut, and it never pays 
to skimp in the question of the trench width either. Usually 
there is not much leeway in the branch location, but it is not 
advisable to cut a pipe nearer than one foot to any bell. By 
cutting a little from the spigot of the branch, and sometimes 
by reversing the branch end for end, a desired flexibility of 
dimensions may be obtained. When the exact location of the 
branch has been settled, then the two points of cutting are 
carefully marked on the existing main, and the pipe thoroughly 
cleaned at these points. The length of the piece to be cut out 
should be about one inch longer than the over all length of the 
branch. In determining the points for the cuts, the effect of 
the bell depth upon the location of the branch should not be 
overlooked. 

After the line of the cut has been chalked on the pipe, if 
the latter is smaller than 12", then by means of a diamond point 
chisel, a cut at least }£" deep is made across the top semi¬ 
circumference. This cut is deepened by repeated going over 
with the diamond point until about half the thickness of metal 


36 




is left. The whole cut is then gone over with a cold chisel, 
after which the chisel is placed in the cut at the top and driven 
into the pipe. It is then removed and a bursting wedge, E, 
Fig. io, inserted and driven home until the pipe cracks com¬ 
pletely around in the line of the cut. The same performance 
is repeated at the other cut, and the cold chisel is not driven 
into the pipe until both cuts are ready for such driving. In 
this way, after the pipe has cracked at the first cut, and is 
temporarily soaped up, there is nothing remaining to be done 
at the second cut except the driving of the cold chisel and of 
the bursting wedge. When the section has broken clear, it is 
hammered out of line, or perhaps it may be necessary to break 
a few pieces out of it to free it. Of course, before the cold 
chisel has been driven in, bags have been inserted to stop the 
gas flow. 

Where the main to be cut is 12" or larger, the difficulty of 
making a crack already started in the cut follow around the 
uncut portion of the pipe increases very much with the size of 
the pipe, and in no class of main work is it more advisable to 
bear in mind the adage of “more haste, less speed,” than in 
cutting large pipe in the trench. It will pay in the long run 
to cut just as large a proportion of the circumference (at least 
three-quarters) as can be gotten at. The cut is made in the 
same way as just described for small pipe. The cold chisel 
should be driven into the pipe not only at the top, but in sev¬ 
eral other places around the cut. Two bursting wedges should 
be used, and great care taken to see that they keep in the 
plane passing through the cut. Otherwise the wedge will not 
exert a pressure tending to crack the pipe along the cut, but 
there will be great danger that they will cause cracks to run 
into the main on either side of the cut. If the cutting has 
been properly done, the main will slowly crack all around the 
circumference as the wedges are driven in. 

Where the pipe is 24" and larger, it is often advisable to 
make three cuts, the third cut being about one foot from one of 
the other cuts. When only two cuts are made, and the length 


37 


of the pipe cut out is considerable, it sometimes happens that 
even after the section is cracked around the circumference at 
both cuts, it remains wedged in the line of main, and requires 
much work to get out. The reason for this is given in the 
next paragraph. Under these conditions, where there is a 
third cut, the bursting wedges are driven into it in such a way 
as to cause cracks each side of the cut, and to break off portions 
of the pipe. After that, it is comparatively easy to remove the 
first section, and then the rest of the cut out section. 

In cutting a line laid with lead joints, the pressure brought to 
bear by the bursting wedges, seems sufficient to make the pipe 
take up at the joints adjacent to the cut, and thus the desired 
separation of the edges of the cut is obtained. With cement 
joints the strength of the joints is apparently too strong to be 
overcome, and so if the pipe being cut is under tension, or in 
other words, is at a higher temperature than when the joints 
were made, the desired separation at the cut will not be 
obtained by the wedges, and in that case it is necessary to cut 
around the entire circumference with diamond points and cold 
chisels, and dispense with bursting wedges entirely. 

In every case, the pipe should be rigidly supported at each 
cut by blocking. Otherwise, there will be great danger of 
cracks being caused in the pipe on either side of the cut out 
section. If one of the cuts, say “A,” comes back of a bell and 
nearer than a foot to it, and the other, say “B,” in front of a 
bell, then it is advisable to force the wedges into “A” and 
sledge away the bell portion before driving the wedges into 
“B.” This program tends to give a cleaner break at “B” than 
would otherwise be possible, but is only applicable when “A” 
is near a bell. 

The process of inserting a branch after the section has been 
cut out, amounts to closing a sleeve gap, and has already been 
described. 

PUTTING ON HUP SPLIT SLEEVE. 

When the connection to the existing main is made by the 
use of a hub split sleeve, that portion of the pipe to be covered 


38 


by the sleeve, is thoroughly cleaned, generally with foundry 
brushes. Then the two pieces of the sleeve are loosely bolted 
around the main, to see first whether the distance between 
outside of main and inside of sleeve is sufficient for jointing 
room, and second, to mark on the main the location of the 
circular cut. The sleeve is then removed and the pipe diamond 
pointed along the marked circle, beginning at the top. The 
cut is then gone over with a cold chisel, going into the pipe, 
except for two inches at the top, where a lip is left to hold in 
place the piece being cut out. A # soaped wooden plug, of 
proper size to fill the opening in the main, is kept on hand 
for use'in case the piece drops out unexpectedly. 

A ring of some soft material, yarn, or wire covered with 
rubber hose is laid around the out side of the cut, and the 
sleeve placed in position on the main and pressing on the ring, 
which forms a more or less gas tight joint, and also prevents 
any jointing material from either end of the sleeve, getting 
into the pipe. The flanges of each half sleeve, if planed, are 
coated with white lead, but if rough, a layer of mill board 
softened in warm water, is placed between the two flanges. 
All of the above bolts are drawn up hand tight and then 
tightened by wrench, no two bolts on the same flange being 
tightened in succession, but the progress being from one end of 
the sleeve to the other, alternating from side to side. 

In making up the joints at each end of the sleeve, if the 
latter is provided with internal ridges, the work is similar to 
any ordinary joint. If there are no ridges, care must be 
taken, if lead is being used, to be sure that the yarning is so 
well done that lead cannot get back past the yarn into the 
sleeve. If it does, a mispour may result. If cement is being 
used, where there are no ridges, yarn is introduced from one 
end for about four inches into the lower half of the sleeve. 
Then cement is put in from the other end of the sleeve until 
‘the yarn is reached. As the level of the cement rises, more 
yarn goes in, until finally the sleeve is filled from the far end. 
The joint is driven from that end, and then cement introduced 


I 


39 


at the other end to fill the four inch space. This cement is 
driven, and the both joints finished in the usual way. 

The actual sequence of events is as follows: When the 
sleeve is bolted tight, a short piece of pipe, or a bend if neces¬ 
sary, is inserted in the hub of the sleeve. Then enough cement 
is put into the sleeve and the hub joint to make them gas tight. 
If a straight piece is in the hub outlet, a wooden plug is placed 
in the end of this piece. This piece is drilled to allow the 
passage of an iron rod, and with the latter the disc piece is 
knocked into the main. The rod is then withdrawn, the hole 
in the plug soaped up, and the sleeve and hub joints finished. 
If a bend is in the hub outlet, the former has been previously 
drilled by a hole so placed that a rod through it will knock out 
the disc piece. In the bend this hole, and in the straight piece 
a specially drilled hole, serves for a bag hole, when more pipe 
is laid. 


PLACING HAT PLANGL. 

In placing a hat flange, after cleaning the main at the desired 
position, the hat flange is tried for fit, it being desirable that 
there should be “iron to iron” contact with the pipe, especially 
at the bolt holes and around the edge of the opening. By 
covering the pipe with red lead and slightly moving the hat 
flange, the high points on the latter are indicated and chiselled 
off. When the hat flange is considered a sufficiently good fit, 
it is held in position, the mark made for the circular cut in 
the main, and the location of the tap bolt holes accurately 
centered by a punch provided with a bushing which just fits 
the "bolt holes. Then the hat flange is removed, and the cir¬ 
cular cut in the main made just as described for the hub 
sleeve. It is advisable to make this cut before the bolt holes 
are drilled, as otherwise there is danger of a crack extending 
between the cut and a hole, under the influence of the constant 
hammering while cutting. 

A hole is drilled and then tapped exactly in the centre of the 
future opening, and into this hole is bolted the “dead man” or 
“old man.” With it in this position, each hole in the main can 


40 


be drilled in succession and then tapped out, soap or clay being 
used to plug the holes as made. 

The face of the flange is covered with white lead, over which 
a linen gasket, previously soaked in linseed oil, is placed, and 
the flange screwed down first hand tight, and then with a 
wrench, tightening in diagonal succession. Around each bolt 
is a piece of lamp wick. Of course, the material used between 
flange and pipe will vary with the individual using it. Mill 
board, canvas, lead, cement are all available. In general, the 
more nearly iron to iron the joint the better. 

The details of inserting an outlet into the hub of the hat 
flange and of removing the disc from the main are exactly 
similar to those already described for the hub sleeve. 

In placing hat flanges, a number of tools are needed which 
are seldom, if ever, used for any other kind of main work, and 
for this reason and also to ensure on hat flange work the 
presence of the necessary equipment, it is advisable to have this 
equipment contained in a special box, which is delivered on 
the work when required. The box is 8 * 4 " x 8*4" x 2 r y" long, 
and contains the following equipment: 

1 “old man” and attachments 

2 6" cold chisels 

2 21/32" twist drills with taper shanks 

1 12" flat file 

2 gauges 

1 4*4 pound ball hammer 

2 diamond points 

1 centre punch 

1 centre punch with bushing for centering 

1 boiler ratchet with 11" handle 

2 24 " bolt taps with square shanks 

1 single-head hexagon screw wrench 

JOINTS. 

YARNING. 

For pipe no larger than 16", one caulker only is needed to 
yarn a joint. The yarn is cut from 1 *4" to 2" longer than the 
outside circumference of the pipe, (and is not good practice 


4i 


to use at any time, any length of yarn shorter than the outside 
circumference), as determined by taking one end of the yarn 
from the bale and passing it around the pipe After a num¬ 
ber of pieces have been measured in this way and cut from 
the bale, a sufficient number of strands are taken from these 
pieces, to make when twisted together, a rope large enough to 
fill solidly when compressed by the yarning iron, the radical 
space between spigot and bell. The proper number of strands 
for the size pipe being laid, having been determined and twisted 
together, one end of the rope so formed is tacked in the right 
hand side of the joint by the yarning iron and pushed at least 
half way in. The balance of the rope is then stretched around 
the pipe, being carefully kept in its twisted state, and driven 
back half way. This method of working, brings the caulker 
around to the right hand side where the yarn was entered first, 
and he continues around a second time, driving the yarn home 
this time. In thus making two circuits of the pipe in yarning 
the yarn remains at all times more nearly in a plane perpendi¬ 
cular to the axis of the pipe, and there is little danger of dis¬ 
turbing the lap. 

Where cement joints are used, only enough depth of yarn 
is needed to support the weight of the spigot end and keep it 
central in the bell without any chance of sagging while the 
cement is setting. Any more than this amount is uselessly 
occupying space needed for requisite depth of cement. It is 
very important that the yarn be solidly driven. Also for 
cement joints, the front yarn is cut and prepared for the 
drivers, and laid across the pipe against the face of each bell 
when back yarn is driven, or at any time after the pipe is lined 
up. This method saves the drivers from carrying yarn from 
joint to joint, it renders uniform the number of strands used, 
not leaving this to the drivers’ discretion, and it prevents dirt 
getting into the joint. . 

Where lead joints are used, the depth of yarn is determined 
by the depth of the bell, and of lead required. Each layer 
needed is put in as was the first, but a new starting point is 
4 


42 


taken, so that the lap of one layer does not come above that of 
a preceding layer. The most satisfactory way to determine 
when enough depth of yarn is in, is to measure back from the 
driving point on each yarning iron the depth of lead desired, 
and stop yarning when the point is touching the yarn and the 
mark is just hidden. 

Mains 12" and larger, being blocked under the spigot end as 
well as the bell end, do not depend on the yarn to hold the 
spigot central in the bell, and, therefore, under these con¬ 
ditions, for cement joints only enough yarn is needed to pre¬ 
vent the cement getting inside the pipe. For mains over 16", 
two men are needed to yarn a joint. The yarn is inserted and 
driven just as described for the small mains, except that each 
man works alternately on his half of the joint until the yarn is 
completely back. Then both men drive at the same time until 
the yarn is properly compressed. 

Jute yarn of a middling quality should be used, with fibers 
long enough to form strands that will twist properly. In this 
yarn a certain amount of oil will always be present, but careful 
buying will eliminate any bales with an excessive amount. 
Tarred yarn should be avoided, as the tar squeezes out under 
driving and deposits a film on the iron surfaces, which is 
detrimental to the tightness of lead or cement. For cement 
joints, some men use yarn soaked in grout, but the general 
preference is for dry yarn, both at the back of the bell and for 
driving, as it is considered advantageous to soak up some of 
the water squeezed out of the cement by driving. On the 
other hand, for lead wool, yarn with a slight amount of tar is 
advisable in order to form d compact mass against which to 
drive the first lead wool strand. By using dry.yarn for the 
last strand, the tarry film is apparently sufficiently wiped off, to 
cause no leak with lead wool. 

The exact weight of yarn required per joint will vary not 
only with the depth of yarn used, but also with the tightness of 
the driving. The schedules below represent New York 


43 


practice with cast lead joints, and Philadelphia practice with 
cement joints: 


New York City Philadelphia 


Size of 
main 
inches 

Depth of 
yarn 
inches 

Weight of 
yarn 
ounces 

Depth of 
back yarn 
inches 

Weight of 
all yarn 
ounces 

4 

— 

— 

Va 

6.0 

6 

2 

2.0 

iV a 

7-5 

8 

2 

2-5 

Va 

9.0 

10 

2 

3-0 

— 

— 

12 

2 

3-5 

Va 

12.0 

16 

Wa 

4.0 

Va 

17.0 

20 

1 y* 

4-5 

Va 

21.5 

24 

2 

5-0 

— 

— 

30 

2 

6-5 

Va 

32.0 

36 

2 

7.0 

— 

— 

48 

2^4 

8.0 

— 

— 


LEAD JOINTS. 

A discussion of the relative advantages of a lead, as com¬ 
pared with a cement, joint will be given when describing the 
latter joint. 

Although depth of bells have been more or less standardized, 
there is much variation in the depths of lead used by different 
companies for the same sizes of pipe. Below is given the 
Philadelphia schedule for sizes to 30" inclusive, and the New 
York schedule for 36" and 48": 

Size of Main. 


a" 

6" 8 " 

I 2 // 

l6" 20" 24 " 

Depth of Lead. 

30 " 36" 

48" 

i#" 

ijV" 2" 

2^" 

a#" 2#" 2#" 

V' 3 tf" 

3>4" 


Approximate Weight. 


6 lbs. 9 lbs. 12 lbs. 22 lbs. 36 lbs. 50 lbs. 62 lbs. 75 lbs. 124 lbs. 165 lbs. 
In considering any depths of lead, it should be remembered that 
the compression due to the most vigorous caulking does not 
extend deeper than about ys' below the surface of the joint. 

While the pipe is being laid and yarned, one pipe man has 
been assigned the job of building a fire under the lead pot and 
having the lead hot when needed. He also brings the red clay 
used for the pouring gate to the proper consistency. The first 






44 


step taken to pour a joint is when a pipe man puts on the 
rubber band, Fig. 13, being careful to drive it back closely 
against the face of the bell while tightening it. At the top, 
a pouring gate is made by the use of red clay, which is also 
smeared around the band where it touches the bell. The 
larger the pipe, the more important becomes all steps taken to 



, Fig. 13. —Rubber Band for Main. Page 44. 

ensure the tightness of the band and prevent any leaking of 
lead. 

For mains as large as 16", the man who put on the band also 
pours the joint. He receives the ladle, A, Fig. 14, (or the 
pot for 16", B, Fig. 14) from the man in charge of the lead 
pot. For 20" and larger, two men are required to carry the 



45 



Fig. 14. —(A) Ladle for Mains 16" and Smaller, (B) Pot for 
i 6 // Main. Page 44. 






46 


pouring pot from the lead furnace to the trench. One of these 
men lowers the pot with a rope and hook and holds the weight, 
while the man who put on the band takes a hook and pours the 
pot. The other man goes back to the lead pot, fills a hand 
ladle, and stands with it resting on the pot, ready to bring it 
quickly if needed. 

On 30" work, two men are assigned to place the band, and 
one of these men stands along side the pipe while the joint is 
being poured, with clay in hand ready to stop any leakage of 
lead. Where it is necessary to use more than one ladle, or 
pot, for a joint, the interval between pourings should be as 
short as possible. If for any reason a joint should not be 
fully run and the lack occurs in the upper half, the surface of 
the lacking portion may be roughened, a gate made around it 
and very hot lead poured. If the lower half of the joint is 
lacking, it will probably be better to cut out the joint and 
repour. 

When the joint has been poured, a short interval is allowed 
for cooling, and then the band is removed and placed on the 
next bell. The joint is now ready for caulking, and for mains 
up to and including 16", there is but one caulker to a joint. A 
caulker should drive five 6" joints each hour, four 8", three 10" 
two and one-half 12", or two 16", the lineal inches of lead as 
measured on the circumference being about the same in each 
case. For 20" and larger pipe, two men are required to a 
joint, and the awkward position in which some of their work 
must be done does not allow the results obtained on the small 
pipe, so that for two men, two 20" joints, one and one-half 24" 
or one 30" will be about the hourly result. 

In caulking, the tools shown in Fig. 15, are used. The 
joint is first chiseled all around between the lead and the spigot, 
being careful to see that no scale, or fillet of lead, is left against 
the iron. After the joint has been chiseled, except at the gate, 
the latter should be cut off, but far enough from the face of 
the bell to allow sufficient lead for caulking. After chiseling 
at the gate, the caulker begins with his smallest tool and en- 



47 


circles the joint. He then repeats this performance with the 
next larger tool, and so on until he has used the largest tool 
possible for the size of pipe being laid. When this is done, 
the joint is completely faced, the lead will be driven about 




flush with the face of the bell, and the joint could in ordinary 
practice be considered finished. Some experiments made in 
Philadelphia in 1901 showed, however, so much greater resist¬ 
ance to strains brought to bear on joints by deflection and 
tension, when these joints had been caulked twice than when 
caulked only once in the usual way, that it is the Philadelphia 















48 


practice to caulk all joints twice. In other words, after the 
joint has been caulked, as just described, each caulking tool is 
again used. Of course, this almost doubles the cost of caulk¬ 
ing, which however, is not a large item in Philadelphia, due 
to the almost exclusive use of cement joints, as will be noted 
later on. 

Each caulker should be provided with a steel stamp, con¬ 
taining a distinctive number or letter, and with this should 
stamp each joint made by him. This identification of work 
has a moral effect which is very favorable to good results, and 
enables the responsibility for a leaking joint to be placed 
against the original caulker. 

* The number of caulkers spoken of as forming part of main 
laying gangs, has been based on cement joints, and more will 
be required where lead joints are made, due to the longer time 
required for caulking lead, as compared with stuffing cement. 

CEMENT JOINTS. 

GENERAL. 

The substitution of cement for lead as a jointing material 
for bell and spigot cast iron pipe is almost entirely a develop¬ 
ment of the last decade, but in that time many thousands of 
cement joints have been made with such favorable results on 
the score of tightness, and of economy in labor and material, 
as compared with lead, that the gas engineer using lead for 
mains under 20" has the burden of proof against him. In 
Philadelphia, in the last thirteen years, 430 miles of cement 
joints have been laid, and in sizes under 30" the number of 
leaking joints is about one to a mile. 

For some time after the adoption of cement for most of the 
small main work in Philadelphia, lead was still used for small 
mains laid in the congested districts, and for all large mains. 
It was thought that as the tendency of 8" or smaller pipe laid 
with cement was to break across the pipe rather than at the 
joint when under a stress, especially one due to construction, 
it was safer to use lead in all locations where other structures, 


49 


especially conduits, abounded, as it seemed preferable under 
those conditions to have a number of small leaks in lead joints, 
than one leak which might quickly fill conduits and manholes 
with an explosive mixture. Cement joints have caused so few 
broken mains, however, that the tendency now is to use cement 
joints in all small mains except possibly when the cover is 
very small, so that stress caused by traffic or temperature is 
apt to be great, or when the renewal of a joint would prove 
very troublesome. One advantage of a lead joint is, of 
course, that if it leaks, simple recaulking will usually effect a 
cure, but the cement joint must be entirely cut out, and the 
conditions under which the joint must be remade are not as 
favorable for a tight joint, as if the pipe was being laid for 
the first time. Dirt is apt to get into the joint, and perfect 
adhesion may not be obtained with particles of the old cement 
left clinging to the pipe. It is also quite evident that if the 
space surrounding the defective joint is rather confined, the 
man cutting out the joint may suffer from the effects of gas. 
For all the above reasons, therefore, lead joints are preferable 
in all special locations where future joint trouble is expected. 

To return to the history of Philadelphia’s experience with 
cement joints, at first it was not believed that cement joints 
could be successfully made for pipe 20" and larger. When 
this problem was solved, as will be described later on, and the 
practice of using cement joints on large mains was adopted, it 
was still thought necessary to put in a lead joint at intervals 
to provide for expansion and contraction. It was believed that 
the joint might prove stronger than the pipe, as is generally 
true for pipe 8" and smaller, and therefore that under severe 
contraction a broken main might result. Naturally a broken 
30" main was not to be desired. Therefore in laying a line of 
30" and of 20" in 1902, lead was used for every eighth joint. A 
comparison of the distance apart of two marked points on 
either side of a lead joint in the 30" line, as between August 
and January, showed that the total movement could be ac¬ 
counted for by the contraction in only twenty-four feet of pipe. 


50 


It is quite probable that the grip of the frozen grouted against 
the pipe is much stronger than any stress due to temperature. 
In any event, as there were no cases of broken 30" or 20" 
mains, but only a few leaky cement joints, two facts were con¬ 
sidered proven: First, that an expansion joint was of no use; 
second, that in a large main the joint was the weakest point. 
This last conclusion removed the final objection to using 
cement joint on large pipe. Ten. years have shown a cement 
joint may leak after being tight for several years, and is then 
much more expensive to repair than a lead joint, but the saving 
in first cost is so great, especially in large mains, and the 
number of leaky joints so few, especially in small mains, that, 
as stated before, the user of the lead joints is put on the 
defensive. 

It seems very probable that most cement joints leak not be¬ 
cause of a temperature stress, but because of settlement of the 
pipe, and where a good foundation may not be secured, lead 
joints may prove cheaper in the long run. In this matter of 
settlement, it has been found advisable with, pipe 24" and 
larger, to let the pipe rest on the blocking at least over night, 
to allow time for the slight compression of the wood by the 
pipe that often occurs. 

material. 

Undoubtedly Portland cement has been used almost exclu¬ 
sively for joint work, even in the early days when natural 
cement was so much cheaper. The material cost is, however, 
so small that few people felt justified in running the expen¬ 
sive risk of having leaking joints through using natural 
cement, generally comparing unfavorably with Portland 
cement in fineness and uniformity in composition. In 
Philadelphia, when starting cement joint work in 1899, the 
Dyckerhoff brand was used and proved generally satisfactory, 
except that at times there were complaints of lack of fineness. 
However, in 1903, American Portland cements began to 
challenge attention, and it was deemed advisable to test various 
brands to see whether one acceptable for cement work could 


5i 


not be found. Not only could price be saved, as compared 
with the Dyckerhoff, but also certain inconveniences inevitable 
in buying an imported article be avoided. As a result of these 
tests, Philadelphia has been using American brands since 1903. 

Each brand was tested: 

First, for solidity under driving. This test consisted in 
noting whether the cement seemed to rock, i. e., act more or 
less like quicksand when being driven. It is quite desirable, 
in driving a joint, that the cement will not rock, but will stay 
where put, so that in driving cement home at one part of the 
joint there will be no lateral displacement resulting in the 
cement rising up at other parts of the joint. 

Second, for activity. A very quick setting cement would be 
objectionable, especially for large mains where the joints take 
some time to make. 

Third, for soundness. The soundness was tested in several 
ways. Freedom from checking or cracking was determined 
by a standard pat test. Expansion was judged by pouring 
grout into some bottles, and ramming stiff cement into other 
bottles, and noting which bottles broke after setting. Where 
expansion is not due to impunities, it is an advantage for joint 
makers. Into some of the bottles red ink was poured on top 
of the cement. If any contraction occurred, the ink would 
find its way between the cement and the glass. 

Fourth, for fineness. This is a standard test and w T as made 
with a No. 80 sieve. 

Fifth, for adhesion. In this test a split sleeve was clamped 
around a pipe and by using grease on one-half of the pipe, a 
joint was obtained between the pipe and one piece of the sleeve 
only. Weights were suspended from this piece until it broke 
away from the pipe. The strength of a cement joint under 
ordinary conditions is measured by the adhesion of the cement 
to the iron under a strain acting parallel to the axis of the pipe. 

MAKING. 

The pipe having been yarned, and well secured from any 
possible movement, by blocking beneath it and by refilled earth 


52 


for three or four feet along the middle of each length, is now 
ready for the joint making process. On small mains the joint 
gang consists of one mixer, one passer, one packer and two 
drivers. The mixer has an iron wheelbarrow, a large pan, 
or a cement mixing board, measures for cement and water, 
and a small short handle hoe. The passer has a trowel and 
a pan, or a mixing board. The passer and packer wear rubber 
gauntlet gloves. The drivers have a caulking hammer, F, 
Fig. io, and a cement caulking tool, G, Fig. io. 

The surface of the bell and of the spigot included in the 
joint have, before the pipe is laid, been very carefully cleaned. 
For this purpose a wire brush, and perhaps gasoline, has been 
used at least a day before joint making, in order to give the 
gasoline time to evaporate. 

The mixer measures out a definite amount of cement and 
water, and mixes it into a thoroughly homogeneous mass. This 
mixing should be done in the shade if possible. There will 
always be more or less difference of opinion as to the exact 
quantity of water to use, some men preferring wetter cement 
than others, but in Philadelphia, the proportion recommended 
is three of cement to one of water by volume. This will make 
a mixture which will appear crumbly in the pan, and will just 
retain the impression of the fingers when squeezed in the hand. 
No more should be mixed in any one batch than can be used 
in the time before setting begins. This time will depend on the 
quickness in setting of the cement being used, as shown by the 
activity tests. Ordinarily, twenty minutes is the maximum 
time that should elapse from the mixing of water with the 
cement to the final work on any joint on which that particular 
batch of cement was used. The mixing pan, or board, should 
be kept scraped clean of all old cement. In practice, of course, 
it is hard to ensure that the mixer will always' follow these 
rules relating to small and fresh batches, but the larger the 
pipe, the more certain it is that carelessness in these matters 
will mean leaky joints. 

A batch being ready,' the passer cuts from it with his trowel 


53 


a wedge-shaped piece and hands this to the packer, who is 
astraddle of the joint. The packer takes the cement from the 
trowel in his gloved hands and starts to pack the joint from 
the bottom. He works up both sides together, finishing at the 
top, using the sides of his hands and fingers to push in the 



Yartx 

Fig. 16.—Cement Joint. Page 54. 

cement. He considers the joint to be fully packed, when on 
pushing his fingers on the lower half of the joint, the cement 
pushes out beyond the face of the bell at some point along the 
upper half. When this is the case, he starts from .the bottom 
and coming up simultaneously on each side, wipes away with 













































54 


the finger tips of each hand, any cement on the spigot outside 
of the bell, and on the face of the bell itself. At this point in 
the process the cement occupies the whole space A-D, Fig. 16. 

The driver now begins by taking up the yarn strands, already 
prepared for him, as described under “Yarning,” and lying 
across the pipe. These he twists if necessary and tucks one 
end in on the left hand side of the joint near the top. He then 
starts to push the yarn in past the face of the bell, working 
down along the left hand side and up the right hand side to the 
starting point at the top. The yarn has then entered the bell 
all the way round, and the excess cement is scraped off by the 
caulking tool and drops to the bottom of the trench. Beginning 
at the first starting point, the driver now goes around the 
joint in the same direction as before, caulking the yarn until it 
feels solid under the caulking tool. The proper amount of 
driving to be done to a joint may not be described, but can be 
learned by experience only. It is quite possible to drive the 
yarn too hard. When the yarn begins to show moisture, this 
is a usual indication that enough driving has been done. The 
driving yarn then occupies the space B-C, and the cement the 
space C-D, Fig. 16. 

After packing all the joints laid out for him, the packer 
starts at the beginning of the line, and fills the space A-B, Fig. 
16 with cement, leaving a surface flush with.the face of the 
bell as shown. This last fillet of cement serves merely to pro¬ 
tect the driving yarn from the soil, not being gas tight itself. 
Rather wet cement of dough-like consistency is used, forty-five 
pounds being mixed at one time on 6" work, enough to make 
twelve joints. 

A gang of five experienced men following the procedure 
above described, can make fifty 6" joints in an hour, or thirty- 
five 8" joints, or twenty 12" joints. For mains 16" and larger, 
the gang is composed of one mixer, one passer, two packers 
and four drivers. The method of working is the same as for 
the small mains. Fourteen 16", ten 20", seven 24" or five 30" 


55 


joints represent what can be done per hour by these eight men 
when experienced. 

temperature: precautions. 

While the use of cement joints on small pipe dates back 
for many years, it is believed that only since 1902 .have cement 
joints on large pipe been successfully made on an extensive 
scale. At that time the Philadelphia Gas Works determined 
to use cement on its large mains if possible, and after a few 
weeks of failure, involving the cutting and remaking of several' 
scores of 20" joints, it was discovered that if the temperature 
of the main was kept nearly constant from the time the joint 
was stuffed until it had set, tight joints would be the rule and 
not the exception, even on 30" pipe. Also, in order to throw 
the least possible strain due to temperature changes, on the 
finished joint, it is advisable to have the temperature of the 
pipe as close as possible to mean underground conditions. 
This, of course, is more easily, or perhaps only attainable, 
when main laying occurs during the spring or fall months. 

Therefore, it is the Philadelphia practice to give preference 
to these months for large main laying, and this is usually quite 
feasible because the need for such mains is seldom so impera¬ 
tive that a delay from winter till spring, or summer till fall, 
is not possible. Small mains, of course, have to be laid at all 
seasons of the year, but fortunately, a given range of tempera¬ 
ture during joint-making and setting does not seem to have 
the same harmful effect on a small, as on a large, pipe. In¬ 
deed some people do not believe it is necessary to take any 
temperature precautions when laying pipe 8" and smaller, but 
such a course will often involve a risk out of proportion to the 
slight saving involved. 

What are the temperature precautions to be taken? To 
begin with, if the pipe has been exposed to the rays of a hot 
sun long enough to become warm, joint making should not 
start until the iron has had a chance to cool to the air tempera¬ 
ture. Ordinarily, pipe can be laid one day and joints made the 
next, in which case there is plenty of chance for the necessary 


5 ^ 


cooling. If, however, joint-making must occur the same day, 
it may be necessary to use water on both bell and spigot ends 
just before laying, to bring down the temperature quickly. 
Neither bell nor spigot should be left wet, for such a condition 
would add undesirable moisture to the cement. It may also 
be necessary when the pipe, after being laid, is exposed to a 
hot sun before joint-making, and there will be no chance of its 
cooling through atmospheric changes, to sprinkle it with water 
applied at frequent intervals by a sprinkling can, or to adopt 
any of the precautions decribed later on as being taken after 
the joint is made. 

The most acceptable time for joint-making on a sunny day 
is in the late afternoon or early morning. The pipe being at 
about the existing air temperature, and joints having been 
made at either of these times, the problem is to prevent a range 
over io° in temperature for the time intervening between 
joint-making and testing. What this time should be will be 
discussed later. If the time is twelve hours, making in the 
afternoon is preferable, as the night range of air temperature 
will usually be less than the day range in the sun. 

The earth that has been refilled midway around each length, 
not only helps to keep the pipe securely in position, but protects 
the covered portion from temperature changes, so that only 
about four feet each way from the joint remains to be pro¬ 
tected. There are several ways of doing this. One method 
very effective, but comparatively expensive and hardly neces¬ 
sary except perhaps for 30" pipe, is to place a few inches above 
the pipe a platform of loose boards, itself covered by six inches 
of earth. The dead air space thus formed acts as an efficient 
insulator, and in very hot weather it may be found advisable 
to build the platform after the pipe is laid, removing it for 
joint-making and replacing while the joint is setting. Follow¬ 
ing this procedure on a line of 30" laid in May, air tempera¬ 
tures under the platform varied in forty-eight hours from 56° 
to 61 0 only, while the corresponding range of the outside air 
was from 53 0 to 74 0 . This record is typical of what is 
accomplished by temperature precautions. 


57 


Another method of maintaining temperatures constant, 
which has proven quite acceptable under ordinary conditions, 
especially with pipe 20" and smaller, is to cover the exposed 
portion of the pipe with coarse bagging, kept wet by 
sprinkling. If the days are hot and the nights cold, it is a wise 
precaution to let the bags dry out towards dark, otherwise 
evaporation might bring about a pipe temperature lower than 
normal. Still a third method, applicable if the trench is 
through a smooth roadway surface and not for pipe larger 
than 20", is to stretch cheesecloth across the trench and by 
keeping this cloth wet, protect the trench from the sun’s heat. 

On cloudy days in spring or fall, often no precaution at all is 
necessary, and even sunny days at these seasons involve less 
air range between night and sun, than is true in summer. 
Severe winter conditions do not have to be considered because 
in such weather, no main laying is done, only repair work. In 
Philadelphia, cement joints are ordinarily used on this work, 
and resulting leaks, if any, have been few. The joints would 
be made as soon as the pipe was uncovered, and refilled right 
after making, so that ordinarily on winter work, the tempera¬ 
ture of ground, pipe and air would not vary far from 30°, dur¬ 
ing the whole period from making to setting. In laying new 
pipe, it does not seem advisable to use cement joints when the 
air temperature falls much below 30°. 

LEAD WOOL JOINTS. 

Many slight modifications of the bell and spigot joints have 
been proposed from time to time, involving a change in the bell 
and 'spigot design, but have never met with any acceptance. In 
the last seven years, however, “lead wool,” a special prepara¬ 
tion of lead in a fibrous or shredded form, has been extensively 
used on mains 30" and larger. Especially notable is its use 
in New York City on 48" pipe. The fibers are put into the 
joint in the same way as yarn, each layer being caulked 
exactly as would be an ordinary lead joint. In other words, 
in making a lead wool joint, the whole set of caulking tools is 
used once for each layer of lead wool used. As a result, the 
5 


53 


labor costs with hand caulking are, on large pipe, from three 
to four times as great as for cast lead. The material costs 
about twice as much per pound, but as less is used, the cost per 
joint is one and one-half times as much as cast lead. On long 
jobs of large mains, the use of pneumatic caulking tools has 
improved the work and lessened the cost, and an experiment 
is being made with a caulking machine, which will still further 
reduce the labor cost. However, the total joint cost will still 
exceed cast lead, and be so far above cement that, even though 
lead wool has almost a zero leak record, yet for pipe 24'' or 
smaller, the argument seems to favor cement. On 30" pipe, 
cement shows more leaks than cast lead, and time alone will 
prove whether the leaks which may finally develop in cement 
joints in this size will outweigh the great saving in first cost. 
Above 30", the choice lies between cast lead and lead wool. On 
isolated work, such as leak repairs, where size of pipe or tem¬ 
perature conditions preclude cement, lead wool will generally 
prove more convenient and, through saving in time, more 
economical than cast lead. 

A fuller treatment of lead wool joints is impossible, both for 
lack of space and of personal experience. The files of the gas 
journals for the last five years contain all that has been written 
on the subject. 

TESTING JOINTS. 

The ordinary small main, laid for low pressure distribution, 
needs no test for tightness prior to refilling, save a test with 
soap suds under gas pressure. The necessity for any test has a 
tendency to delay main work and increase expense, and this 
is especially true where the test is made by pumping air into 
the main. Experience has shown that the test with gas is 
sufficient under the conditions described. The suds are applied 
with an ordinary shaving or other suitable brush, over the face 
of the joint and the adjacent spigot and bell, and any leak in 
the joint will be indicated by the presence of soap bubbles. 
There will be times when it is advisable to refill as soon as the 
joint is made and to omit any testing whatever, as for instance 


59 


where the trench cannot be kept open for any length of time, 
or when cement joints are used and temperature conditions are 
hard to maintain. In New York the success with lead wool 
joints has been so great that no test is made. 

When the main is being laid by contract, or when it is larger 
than 12", it is good practice to make a test under air pressure 
of three to five pounds. Observations of a pressure gauge in 
connection with a soap-suds test of all joints, will indicate the 
degree of tightness secured.. If possible, the test should be 
made at a time when the range of air temperature is small, for 
in a large main there might be a stationary or slightly rising 
pressure, even when there are a few large leaks. Of course, 
the possibility of this occurrence is greatly increased if the 
line under pressure is quite long, as is often the case where 
each successive section laid is joined to the preceding sections 
and air pressure applied to the whole line. Where each section 
is tested alone, and the length of line under pressure does not 
exceed one thousand feet, the gauge is more independent of 
temperature, but at the same time temperature must always 
be borne in mind. It is possible with falling temperature, to 
have a falling gauge on a perfectly tight line. 

When any fall in pressure cannot be accounted for by tem¬ 
perature conditions and yet every joint shows tight, a search 
should be made for a cracked pipe. It is a very foolish act to 
pass a line, especially of large pipe, on a falling pressure until 
every inch of main has been carefully examined. 

For any volume up to 2,000 feet of 30" pipe, the air pump, 
Fig. '17, is sufficiently large. For a larger volume, a steam 
driven pump could be used to advantage, unless the amount of 
use would not justify the outlay. Outfits are obtainable in 
which boiler and pump are mounted on a wagon frame, and 
so may be easily drawn from place to place. 

Below follows a method used in Philadelphia for an air test. 
The test is usually made as near 7:00 a. m. as possible. The 
night before, all openings in the main are plugged up, the air 
pump is attached to the main, and the mercury gauge is 


6o 


examined and made ready for attachment. In attaching the 
air pump, a iJ4" hole is tapped either on the main or prefer¬ 
ably, in the closing plug or cap. Sufficient ij 4 " pipe provided 
with suitable fittings to allow a y%" connection with the gauge, 



Fig. 17.—Air Pump. Page 60. 

is used to place the gauge in a convenient point for observation. 
Armored hose connects the ij^" pipe to the pump. 

Arrangements are made to commence pumping at such an 
hour in the morning that the required pressure will be reached 
at 7 :oo a. m. With the pump shown in Fig. 17 for a pressure 


/ 




6i 


of three pounds in five hundred feet of 30", four men would 
be needed for two hours. The test is made by two men with 
pound brushes and a bucket of ivory soap suds. A foreman 
supervises the work and marks any leaks as found. When the 
test is completed, the pressure should be relieved through the 
standpipe or in any other way, before removing the plug or 
cap at the end of the section under pressure, as, if not, there is 
danger of injury to the workmen. 

PRECAUTIONS AGAINST SETTLEMENT. 

After a pipe is laid and covered up in a tight condition, the 
only reasons to cause breaks or leaky joints are some agencies, 
usually human, acting during subsequent exposure of the pipe; 
stresses due to street traffic and to temperature; and settlement 
of the pipe itself. The first danger must be guarded against 
by efficient line walking, the second and third are affected by 
the depth of the pipe, and the fourth, to which is due many 
leaky joints in all sizes of pipe and many breaks in small pipe, 
will be considered now. 

Supposing, as is generally true, that the trench is in firm 
ground, the theory used to be that the pipe should be laid on 
this firm trench bottom, proper excavation being made for 
each bell. This theory worked all right in practice where 
obstructions were few, and therefore no occasion arose to 
decrease the expected cover of the pipe after the trench was 
bottomed; and, more important still, where the gang was small 
in number and contained one or more laborers skilled in making 
a bottom that lay in one plane, and was not formed of a series 
of small planes. The above conditions were never obtainable 
in towns of any size, and usually the result of laying directly 
on the earth was a line supported at a series of points along 
each length, and occasionally resting on refilled earth where 
the original trench depth was too great. Trouble has fre¬ 
quently resulted from such conditions, and, of course, more 
often with large pipe, with resulting heavy repair cost. 

A little reflection will show that without any earth com- 


62 


pression, the support of a length lying on the earth, is a line 
about eleven feet long. If, as would be usually done, the pipe 
was allowed to drop on its bed several times, then assuming it 
always fell in the same place, there would be a concave bed 
probably several inches wide. Actually, however, it would be 
impossible to get any greater bed than one dropping would 
accomplish, and if such dropping did not leave the pipe in a 
straight line with the pipe already laid, a crook must be left 
in the line, or the bed disturbed. 

The use of blocking obviates the difficulties above mentioned. 
The trench need not be carefully bottomed except where the 
blocking rests. In setting the block, paving rammer should be 
used to ensure that the block has a firm bearing over its whole 
area. Another good way of bedding the block is to raise the 
bell end of pipe about two feet, and then allow the latter to fall 
free on the block. The pipe can now be freely moved side¬ 
ways on the block, or up and down by inserting distance pieces 
and wedges, with the certainty that its stability is not being 
affected. The use of wedges and of the distance pieces of i" 
board enables an exact alignment as to height, something im¬ 
possible to obtain when laying on the trench bottom. 

In deciding on the sizes of blocking to be used for various 
sized mains, there is ample opportunity for the use of in¬ 
dividual judgment. Below is the schedule used in Philadelphia: 

Schedule of Blocking. 



Size of blocking. 

Size of distance pieces. 

Size of wedges 

Size of 
mains 

Thick¬ 

ness 

Width Length 

Thick¬ 

ness 

Width 

Length 

Thick¬ 

ness 

Width 

Length 

3" to 8" 

3 " 

I 2 // I2 // 

I " 

12 " 

\ 2 " 

I#" 

4 " 

6" 

IO // to 12" 

3 " 

12" 18" 

l" 

12" 

\ 2 " 

2" 

5" 

8" 

16" to 20 /r 

3" 

12 " 2 \" 

l" 

I2" 

24" 

3 " 

5" 

i 2 // 

24" to 30" 

\" 

12 " $o" 

I" 

12 " 

24" 

3 " 

5" 

I2 7/ 


For services use 2" x8"—8". 

The blocking must always be used of full width and 
placed upon undisturbed earth. For mains over 16", two 
blocks are laid side by side at each blocking point, making 
the width of four blocks for each length. 

This schedule may be considered by some as being too 






63 


liberal, but it was designed with the knowledge that a few leak¬ 
ing joints under asphalt would pay for many feet of lumber. 
Two inch blocks undoubtedly could be used for small pipe, but 
3" will last longer, and the extra thickness may be needed some 
day to prevent settlement, where a block has been improperly 
imbedded. The blocks have been made short and wide rather 
than long and narrow, because the more nearly square the 
block is, the more apt is it to bear on its whole surface. A 
block which is almost as long as the trench is wide, will require 
great vigilance on the foreman’s part to prevent many such 
blocks being set, resting on earth only at each end. 

The surface area of the blocking for each size main as given, 
causes a pressure per square inch of such surface, which is 
the bearing surface of the blocking on the trench, varying from 
thirty-two pounds in the case of 8", to ten pounds for the 24 , 
the weight taken being that of a pipe itself and a parallel- 
opipedon of earth, three feet high, twelve feet long and of 
width equal to the outside diameter of the pipe. For pipe 
over 8" in size, there are two blocking places in each length, 
and this enables a positive support to the spigot end, which is 
of great advantage in making cement joints, as it enables less 
yarn and more cement to be used, and prevents any settling of 
the spigot with a consequent leak. Where more blocking area 
is needed than will be given by two blocks to a length, four 
are used, two at each blocking place. In this way, 3" x 12" 
lumber can be used for all blocking, the only difference between 
the various blocks being in their length, and these latter have 
been so arranged that some of the larger blocks may be cut to 
form two smaller blocks. 

There is only one objection worth noting to the use of 
blocking. This is the space left between the main and the 
trench bottom. The question of refilling this space will be con¬ 
sidered later. As already stated, a little care in insetting the 
blocking in the trench bottom will reduce the space to rather 
less than one inch in height, and this care should be exercised 
especially with larger mains. 


6 4 


Blocking will care for the ordinary conditions of main lay¬ 
ing. Where the soil is of uncertain stability, or the weight 
exceptional, as with some special castings, especial methods 
might be used. Short piles may be driven into the trench 
bottom at each side and the blocking rest on them. Concrete 
or brick piers may be built. Such piers are often advisable 
under specials, particularly bends used where the main changes 
in cover, and a big pile of blocking would otherwise be re¬ 
quired. In every case, however, the pipe itself should rest on 
wood and not on the pier direct. 

BAGGING. 

NECESSITY FOR BAGGING. 

No matter how small the pipe, no connection should be made 
to a main either by a cut out or by removing a plug or cap, 
without first stopping off the flow of gas. There are many 
workmen and some foremen who object to this precaution in 
the case of 2", 3" or even 4" mains, and who, if left to their 
own devices, would often “jump in” a connection without 
stopping off the flow of gas. Such a practice, however, should 
not be tolerated, as it involves too much risk to the workmen, 
and also to the maintenance of gas supply on the main con¬ 
cerned. 

In the old days of small mains, animal bladders served fairly 
well, and there was nothing better until the advent of rubber 
bags, which in turn, within the last decade, have been largely 
' supplanted by stoppers. 

Of course, the larger the main, the more dangerous would 
be the result of unrestricted flow, and, therefore, the more care 
that is necessary in the provisions for stopping off this flow. 
In Philadelphia, one bag or stopper must be used to prevent 
gas flow in mains 8" and smaller, and two bags, or two stoppers, 
or one bag and one stopper, for larger mains. The last com¬ 
bination is to be preferred, especially in the very large mains, 
where the stopper is not apt to fit close enough to prevent a 
leak sufficiently large to bother the workmen. Ordinarily, a 


65 


separate hole is tapped for each bag, or stopper, and the latter 
is placed farthest from the opening, in other words, towards 
the gas flow, and takes up the pressure, so that the bag simply 
prevents what little gas may be going past the stopper, from 
getting into the portion of main being connected. This is on 
the assumption that a wrought iron “bleeder” pipe varying in 
size from i" to 2" is inserted into the tap hole for the bag, and 
that through this pipe there escapes into the air, well above the 
top of the trench, any gas leaking past the stopper. There may 
often be cases when a bleeder pipe is not necessary. If so, of 
course the bag stands the full pressure differences, but the first 
stopper is the safeguard against any great gas flow, in case the 
bag should break. 


SIZE OF BAG HOLES. 

The schedule in use in Philadelphia, governing the sizes of 
holes to be tapped for the insertion of bags and stoppers, is as 
follows: 


Size of main 

Hole for bag 

Hole for stopper 

3" 

l" 

l" 

4" 


I#" 

6" 

I 

itf" 

8" 

2" 

2" 

10" 

2" 

2" 

12" 

2 


16" 

*3" 

-// 

3 

20 " 

*3// 

„// 

0 

24" 

4" 

4" 

3°" 

4" 

\" 

36" 

4" 

4" 


,*4 /7 will be needed for the heavy canvas bags. 

INSERTION AND WITHDRAWAL. 

I11 inserting a bag, the procedure is about as follows: After 
the hole has been drilled, the portion of the main where the bag 
will rest, is carefully cleaned of any metal cuttings, or any con¬ 
densation, the latter often having a very rapid action in dis¬ 
solving rubber. This cleaning is accomplished by means of 
waste or cloth at the end of a stick. Where condensation is 


66 


encountered it is advisable by soaping to protect the bag as 
well as may be. Soap will also help in making a bag hold 
back gas where the inside of a main is quite rough. If it is 
thought desirable to use a bag saving device, this is now 
screwed on. 

The bag fork, I, Fig. io, is sometimes used in inserting the 
bag, which is placed in a folded position on the face of the 
fork, and the bag stem pulled back between the prongs near 
the hilt. The bag and fork are then entered simultaneously, 
the fork serving to force the bag down into the main and away 
from the hole. After inflation of the bag, the fork is with¬ 
drawn. Where there is much more pressure on one side of a 
bag than another, the fork is of special use in holding the bag 
in place until inflated. In the absence of a bag fork, a stick 
is used to force in the bag, which is always snugly rolled or 
folded. 

A bag is properly placed when the axis, passing through the 
stem, coincides with the axis of the main. In inflating large 
bags, a bag pump, B, Fig. 18, is generally used. By means of 
a small bag inserted in the supply line, an indication is given 
of the degree of inflation of the bag in the main. This also 
can be told by observing the bag itself through the bag hole. 
Large bags have cocks attached to their stems to control the air 
flow. The stems of small bags are tied together in a kinked 
position. A small stick should be attached to the stems of all 
bags in such a way as to prevent the bag from being forced 
away from the bag hole. All bags or stoppers, while in use, 
should be under constant supervision to ensure that they are 
maintaining their inflation and position. 

In removing a bag, the air is first allowed to escape, and then 
the bag is slowly pulled out through the opening, first, by 
means of the neck, and then by pulling on the bag itself, the 
pull being always applied close to the main, and the bag kept 
rolled up like an umbrella. All condensation should be im¬ 
mediately removed from the bag by the use of soap and warm 
water. 


67 


In inserting a stopper, A, Fig. 18, it is neatly folded and 
pressed together, and pushed in carefully and slowly, it, as well 
as the bag, being always a snug fit in the hole allowed by the 
schedule. The flexible frame and the handle are kept upper¬ 
most until the stopper is completely within the main. The 
top of the flexible frame is then in contact with the top of the 
main and a short distance back of the hole, the bottom of the 



Fig. 18. — (A) Stopper, page 67. (B) Bag Pump, page 66. 

frame is on the bottom of the main, and the axis of the top is 
at an angle of about 45 0 with the axis of the main. The 
stopper is now revolved through 180°, and pushed into the hole 
about as far as it will go, bringing the top of the frame a few 
inches from the hole. The top is kept in this position, or 
perhaps forced slightly away from the hole by means of the 





68 


short handle, while by the long handle the lower end is drawn 
forward towards the hole, thus bringing the plane of the frame 
into perpendicularity with the axis of the main, and forcing 
the frame into a circular shape. When ready to draw the 
stopper, the lower end is forced back along the bottom of the 
main, and the upper end is drawn slightly forward, until the 
frame has assumed its greatest possible length. The stopper 
is then revolved i8o° bringing the frame on top, and with¬ 
drawn. 

CARE IN REGARD TO SUPPLY OF GAS. 

Gagging off the supply of gas involves certain operations 
which, unless precautions are taken, may result in a diminution, 
or entire stoppage, of supply to consumers. These operations 
are: First, the tapping of the bag hole and any subsequent 
opening of it, allowing free gas flow; and second, the insertion 
of the bag with a consequent interruption of gas flow in the 
main. 

The precautions to be observed in connection with the 
tapping of the bag hole, of course, apply equally to the tapping 
of any hole for any purpose, or to any work which makes in 
any pipe conveying gas, an opening whose area is of appreciable 
size as compared with the area of the pipe. Experience has 
shown that if flow is quickly established through the ordinary 
hole tapped in the average size main, the diminution in pressure 
caused thereby, may be quite sufficient to put out lights turned 
low, and that the quick uncovering of the opening, causes the 
pressure in the main to fall momentarily to a point lower than 
is caused by the steady flow of gas through the opening. Of 
course, the amount of effect produced in any main, that is, the 
number of feet each side of the opening that the effect extends, 
and the extent of pressure lowering, depends entirely upon the 
relation between size of main and of opening, and the condi¬ 
tions affecting the supply of gas into the main. However, 
such serious results may ensue from unlighted gas issuing 
from burners, extinguished by a lowering of pressure, because 
of the careless tapping of holes and their uncovering in putting 


6 9 


in bags, that it is wise, especially in cities and large towns, to 
observe the following precautions. 

When any opening is made between a main and the 
atmosphere, so that gas may escape from the opening, the plug, 
tap, or fitting, the removal of which makes the opening, should 
not be moved away from the main at right angles to it, but 
should be moved sidewise over the opening, and kept in close 
contact with the main, and as it is moved off the opening, the 
fitting, or plug, which is to take its place, should be moved on. 
Neither motion should be rapid or sudden. The result will be 
that at no time is the whole area of the opening exposed for 
the escape of gas, and also that there is no rapid change in the 
area through which gas is escaping. 

When a hole has been tapped for the insertion of a bag (or 
stopper) and the bag is to be inserted at once, in removing the 
tap from the main, it should be slid sidewise over the hole and 
followed immediately by the hand, placed in such a position as 
to partially encircle the receding tap, and to block off the escap¬ 
ing gas as far as possible. In inserting the bag, the hand 
should be moved slowly over the hole to afford room to insert 
the end of the bag, and the hand should continue to cover the 
hole as much as possible, until the latter is filled by the bag. 
As the bag gets further in and begins to taper off towards the 
top, the hand should again be placed over the hole, and kept 
there until the bag is inflated. In withdrawing the bag, the 
same precautions should be observed in reverse order; and, in 
general, everything done which will decrease the absolute 
rapidity of gas flow, and the rapidity of change in amount of 
flow. 

The practice described above should be followed in mains 
of all sizes. In addition, where the main is 3" or smaller, or 
is supplied from only one end, and any portion of this sole 
supply is 3 ,/ or smaller, a pressure gauge, as shown in 'Fig. 19, 
should be connected with the main so that any pressure 
drop can be noticed, and, if at any time as little as 1.0" pressure 
is shown, then an examination must be made in the neighbor- 


7 o 


ing houses to make sure that no lights have been put out. In 
general, in any work involving possible interference with the 
evenness of gas flow, any nearby street lamp supplied from the 
main in question should be lighted, as its flame will be a val¬ 
uable telltale of what is happening in the main. 

Discussing now the second precaution, viz., what will be the 
effect of the insertion of the bag in that portion of the main 
which must not be deprived of gas, the whole question hinges 
upon what is known of the main connections in the region in 
which the work is being done. Where the records are per¬ 
fect, and show that a main is connected at both ends, then in 
the absence of a stoppage, such as water in a trap, or a drip, or 
some other obstruction, a bag, or bags, may be inserted with 
confidence that the result will be the stoppage of supply to that 
section of main only, whose isolation is desired. 

If, however, it is necessary to bag off a portion of a main 
which is not positively known to be supplied from both ends, 
the work should be done according to the following directions, 
as illustrated by Fig. 19. Place a bag (or stopper) through 
the hole at “X” in the position “A,” Fig. 1, judging the flow of 
gas toward the bag by noting the speed of the gas escaping 
from the bag hole. The escape of gas thus permitted should 
be brought on gradually for reasons already explained. If no 
drop in pressure is noticed, deflate the bag, inflate in position 
“B” and test for flow of gas as before. If this test indicates 
a satisfactory flow, leave bag in position “B.” Another bag 
inserted through bag hole “Y” in position “C” completes the 
operation of isolating the portion of the main to be repaired or 
removed. The tests at “X” have demonstrated that gas was 
being supplied in both directions, and that therefore no by¬ 
pass is necessary. 

If on making test with bag in position “A” or “B,” a drop in 
pressure is noted, indicating some obstructions or a dead end, 
the bag should be left in position inflated until the extent of 
the section deprived of gas is ascertained and the meter cock in 
each house closed. (This same routine should be followed in 


71 


any case of bagging off a main where it was discovered that 
gas had been shut off from a section not meant to be isolated). 
Having done this, the bag may be deflated and gas again 
allowed to flow into the section unintentionally isolated. Be¬ 
fore resuming the work necessitating the bagging, a siphon 
gauge, Fig. 2, should be attached to the section previously 
isolated and a by-pass laid around the section to be bagged 
off. Observations of the gauge should be made while insert- 



Fig. 19.—Pressure Gauge. Page 70. 


ing or removing by-pass, bags, etc. If at any time the pressure 
falls below 1.0", the gas should immediately be shut off the 
section so affected, and an examination made of each house as 
already described. Fig. 2 shows the position of the bags and 
by-pass when ready to cut out or repair under the conditions 
already described, in other words, the arrangement necessary 
when the main is fed from one end only. 























When withdrawing the bags in the arrangement as shown in 
Fig. i, on completion of the work, the bag (or bags), which 
was the first to be inflated, should be drawn first, and the 
resulting pressure noted. In this way, if by any chance the 
supply of gas has been unknowingly cut off on the side of the 
section first bagged off, this fact will at once be shown on with¬ 
drawing the bag, by the entire absence of pressure, and the 
proper precautions can be taken. When, as in Fig. 2, a by¬ 
pass is in use and in place, the first bag inserted should be at 
“L” in the dead end supplied by the by-pass, being placed as 
shown on the side of the hole away from the section to be 
repaired or removed. This bag must be the last one with¬ 
drawn, for the full supply of the main, in addition to the by¬ 
pass, must be available to the dead end section as the last bag 
is being deflated, or otherwise the escape through the hole 
“W,” even with every care exerted, might be sufficient to 
render the supply through the by-pass insufficient to keep up 
the pressure in the dead end section. 

PURGING. 

The operation of “purging,” i. e., filling a main with gas. 
may be either very easy or very difficult, according as there 
happens to be a small length of main, or an extensive system 
to be dealt with. In every case, however, care is needed to 
prevent any chance of ignition of the explosive mixture of gas 
and air issuing from the main being purged. 

In its simplest form as applied to a stretch of ordinary size 
main, ending in a location where a little gas smell is not 
objectionable, purging consists of removing a screw plug from 
a hole tapped in the main at the end farthest from the source 
of supply, and allowing first the air and then the mixture of 
gas and air to blow into the atmosphere until either by smell, 
or by sampling the issuing gas, it is believed, or found, that 
all the air has been removed. The advisability of sampling 
increases with the size of the main, and with the chance of the 
mixture of gas and air being supplied to consumers before any 


73 


other operations to produce a flow of gas through the main in 
question, and, therefore, to reduce the air to a negligible per¬ 
centage. 

1 he sampling may be accomplished by filling with the issuing 
gas a deflated rubber gas bag, and then removing the bag to a 
safe distance, inserting a pipe with a burner attached, in the 
stem of the bag, squeezing the bag and lighting the stream 
issuing through the burner. The color of the flame will 
indicate how nearly pure gas the bag contains. 

With an increase in the size (and to some extent the length) 
of the main, will result an increased volume of gas and air 
to be discharged into the atmosphere, before purging is com¬ 
plete. This will often mean the advisability of a standpipe 
screwed into the outlet hole, and discharging above the heads 
of pedestrians. Also, as the period in which an explosive mix¬ 
ture exists, is longer, than with a small main, the use of wire 
gauze in the standpipe is a wise precaution. This gauze pre¬ 
vents any flame which might ignite at the standpipe end, from 
flashing back into the main. 

In every case of purging, the precautions already spoken of 
under “Care in Regard to Supply of Gas,” should be carefully 
observed. After the main is considered to be properly purged, 
the plugs of all drip standpipes should be removed, to allow the 
escape of any air that might be pocketed in the lower portions 
16" and over, is shown in Fig. 20. The convenient method 
for sampling the gas will be noted. 

Very rarely it may happen that the main to be purged is 
situated where the escape of gas would create a considerable 
nuisance, as in a crowded business thoroughfare. If so, if it 
is not advisable to purge until the smell comes and then stop, 
trusting to the sufficient admixture of the air remaining with 
the gas, to prevent any chance of lights going out, or of very 
poor illumination, the only remaining course is to burn the 
issuing stream at the top of the standpipe. With a gauge of 
mesh as small as that used in safety lamps, and a standpipe 
6 


74 


equipped with four successive sheets of gauze, arranged in two 
of the drip pots. 

An arrangement that has been used in Philadelphia on mains 



pairs, two feet apart, each sheet of a pair being separated by a 
^2" gasket, there would seem to be no risk of any flashing back 
in the main, if care is taken to observe that the pipe is not 
becoming warm, for a reason now to be told. 





























75 


In supplying New York City with gas made on Long Island, 
it happened that fifty miles of mains were laid before the 
tunnel under the East River was completed. Therefore, this 
main system had to be purged more or less as a whole, and it 
was actually purged in two sections. It was decided to burn 
the gas in order to be sure that all of the air had been expelled. 
Standpipes with four gauzes about as described above, were 
successfully used on this occasion and also on each subsequent 
addition to the main system, until one day, when purging about 
one thousand feet of 20" main, an explosion occurred, due un¬ 
doubtedly to the flame at the end of the standpipe flashing 
back into the main. The only explanation for the passage of 
the flame back through the four sheets of gauze, would seem 
to be that the flame first flashed back to the upper pair of 
gauzes, and burned above them so long as to make them red 
hot. In this case the flame would travel down to the second 
pair, and after they had become red hot, an explosion could 
occur if the mixture was still explosive. An observation of 
the temperature of the standpipe would have disclosed the fact 
of the flame burning on the gauzes, and the danger being 
incurred. 

A feature of purging where more than a single line of main 
is in question, is the necessity for bagging at certain points to 
prevent large pockets of air. For instance, when one or more 
of the mains is fed from both ends, three bag holes, with a bag 
in the centre hole, will allow the air to come both ways to the 
bag, and issue out of the other two holes without forming any 
pocket. Naturally, in work of this kind, the tightness of the 
bags is very important, and each such bagging place should be 
under the continuous surveillance of a reliable workman. 

MAINTENANCE OF GAS SUPPLY DURING. MAIN 
LAYING. 

IMPORTANCE OF MAINTAINING SUPPLY. 

So far, in discussing the question of main laying, it has been 
assumed that the work involved an extension into new 


?6 


territory. Many mains are laid, however, to replace existing 
lines, and in these days of the extensive use of gas for heating 
and other domestic and industrial purposes, it is often im¬ 
perative, with any due regard for the rights of the consumer, 
that any cessation in gas supply be as short as possible. This 
means to begin with, that gas supply be kept up either through 
the existing main or temporary main, until tfie new main has 
been purged. If gas is maintained in the existing main, but 
this must be disconnected from its ordinary source of supply; 
to allow the connection of the new main, then a by-pass must 
first be installed across the gap. It also means that the 
transfer of old service to new main, or from old main and old 
i service to new main and new service, should be done 
expeditiously. 

In considering this work, three different conditions will be 
taken up in turn: First, where the existing main is not in the 
way of the new one, and therefore can be kept in use until the 
main has been purged; second, where the existing main must 
be removed to make way for the new one, but prior to such 
removal a temporary main may be laid; and third, where the 
existing main must be removed, but no temporary main is 
feasible. 

SUPPLY BY EXISTING MAIN. 

Where the existing main, whether or not exposed in the 
trench made for the new main, may continue to supply gas 
until the new main has been purged, the work of main laying 
is not much more different than in the case of new extension, 
except for what support may have to be provided for any 
section of the existing main that may be exposed in the trench. 
At this point, it should be stated that the value of the iron 
recovered, even at scrap prices, generally makes it an 
economical proceeding, other considerations being equal, to 
lay the new main in such a location that the existing main may 
be removed with either no, or only a slight amount of addi¬ 
tional excavation. 

Before the new main is purged, all necessary service holes 


77 


should be tapped, and service renewals made to within the 
cellar wall. Then in the case of a consumer whose service 
was renewed, the discontinuance of gas supply, will only cover 
the time necessary to transfer the piping on the inlet side of 
the meter, from the old service to the new one, which may in¬ 
volve only the unscrewing of the existing inlet connection, and 
the screwing of a new inlet connection attached to the new 
service. When the service does not need renewing, there will 
be necessary, in addition to the work inside the cellar and 
preceding it, the cutting of the existing service and its recon¬ 
nection to the new main. The above service details apply 
equally as well to the paragraphs that follow. 

SUPPLY BY TEMPORARY MAIN. 

Where a temporary main is to be laid, its size should be 
determined from accurate knowledge of the maximum demand 
of the consumers to be supplied. Usually a 2" or 3" main will 
be amply large, and wrought iron is generally preferable for 
any size smaller than 8". The location is normally above 
ground and close to the curb, either in roadway or on footway. 
Tees forming part of the line of pipe, make the best method 
of service connection. Each tee is joined by iron pipe, or by 
pipe and armored rubber hose to one of the existing services. 
This involves a cessation of gas supply while the service is 
being cut off from the existing main and connected to the 
temporary main. Generally, the connection to the service will 
be made outside of the curb cock, but even in that case, it will 
be advisable, when using hose connection, to put a cock be¬ 
tween the hose and the outlet from the temporary main. This 
second cock allows a quick shut-off in case the hose connection 
pulls off or in any way develops a leak not capable of quick 
repair. 

The temporary main will usually be supplied with gas 
through one (or preferably two) connections tapped into the 
existing main system. In the case now under consideration, 
viz., where a temporary main is used only during the laying of 
a new main, it is seldom necessary to make any provisions for 


78 


condensation in the trap formed by the service connection 
above described. Where, however, temporary mains are laid 
because of the forced removal of permanent mains during the 
progress of street work, and temporary supply will continue 



Fig. 2 i.v— Temporary Main. Page 78. 

during cold weather, ample drip provision should be made at 
any trap. 

Figs. 21 and 22 illustrate some features of temporary main 
work. 


SUPPLY IN ABSENCE OF ANY MAIN. 

The case in which the existing main must be removed to 
allow room for the new main, no temporary main was 
possible, and consumers were using gas at all hours of the 
day, would undoubtedly prove to be very rare. Where the 
existing main was fed from two directions, it could be cut out 
at the end from which the new main was being laid without 
installing a by-pass. Then the problem of main laying would 




79 


consist in removing the existing main in as small units as 
seemed practicable, and in purging the new main in small 



Fig. 22.—Temporary Main. Page 78. 

sections as laid. Holes for services would be tapped in the 
new main before laying, and would serve as successive purging 
and bag holes. In this way, no consumer need be out of gas 





8 o 


more than one or two hours, and by special expedients this 
time could be greatly reduced. For instance, a temporary 
pipe might be run from the top of the street tee in the last ser¬ 
vice on the new main, to connect with the service, or services, 
being disconnected from the section of existing main just 
taken out to make way for the next section of new main. 

Where the existing main was only fed from one end, and 
this was the end from which the new main was laid, a by-pass 
would, of course, have to be installed to feed the existing main, 
and with the progress of the new main, the position of the 
by-pass would be continually changing. 

REFILLING. 

GENERAL CONSIDERATIONS. 

In refilling, there is always an opportunity of skimping 
work, entirely absent in the case of trenching. The great 
saving in labor afforded by loose filling or puddling, as com¬ 
pared with tamping and ramming, often results in the adoption 
of one or the other, where not only the best interests of the 
work, but also of the public, require that ramming should be 
done. In discussing the conditions that should be kept in 
mind in deciding on any particular method, this general rule 
should never be forgotten, viz., that the public has a right to 
expect such refilling as will restore as promptly as possible to 
its original condition, the surface of any trench in any road¬ 
way, where traffic is seriously incommoded until such restora¬ 
tion is complete. 

Unless the expense is very great, only good soil should be in 
'dose proximity to a main, and cover it by a layer six inches to 
a foot thick. This is especially important where the main is 
of wrought iron or steel and the good soil is substituted for 
ashes, cinders or city refuse. Cast iron is not nearly so sub¬ 
ject to corrosion, but still good soil around it is advisable. The 
objection to refilling with small or large stones or broken rock, 
hinges entirely on the question of future repairs. If the trench 
i$ not apt to be opened to any great extent, as would be true 


8i 


of most small main jobs, a large expense for soil to replace the 
excavated rock would not be justified. However, it often 
happens when solid rock is encountered, that the excavated 
material can be sold on the trench side at a slight profit, thus 
paying for the substituted earth. 

During the winter time when the excavated earth freezes, it 
should be broken up as far as feasible, both as excavated and 
after being frozen, before refilling, because the larger the 
lumps replaced, the less the material returned to the trench, 
and the more settlement occurring after the frost goes out. 
As far as possible, unfrozen material from the centre of the 
pile should be placed around the pipe. When other condi¬ 
tions are acceptable, and the temperature is not so low that 
the water will freeze, instead of thawing the frozen lumps, 
puddling may be used to advantage with frozen material. 

The character of the temporary surface over the trench in 
those cases where repaving does not follow immediately upon 
refilling, will vary with the kind of paving and will be dis¬ 
cussed under the head of “Repaving.” 

RAMMING/ 

Ramming should be the practice wherever there is much 
travel along and over the trench, or where repaving must follow 
immediately. It is accomplished by tamping and ramming 
solely, or in combination with puddling. 

If the main has been laid with cement joints, dirt has been 
tamped under and along side of, and rammed on top of, the 
pipe a depth of several inches, except at the bell holes. If 
lead 'has been used, the amount of refill that has been done 
prior to the completion of laying work, will depend upon the 
necessity for strengthening the trench or keeping the laborers 
busy. In any case the first refilling work after the pipe has 
been laid, tested and purged, is to cover any existing uncovered 
portion of pipe, and where compact filling is necessary, there 
should be for every shoveler on the bank two men in the 
trench, tamping the earth under the pipe and between it and 


82 


the trench sides, and then after the pipe has been covered, or a 
sufficient width of trench reached, changing to a rammer. 
When first tamping around a pipe, which is not held in posi¬ 
tion by any earth, the tampers should be in pairs, one on each 
side of the pipe, working against each other and thus preserving 
the alignment. Both in tamping and. ramming, the lowest 
point on the trench should be refilled first, and the refilling 
thereafter carried on in horizontal planes. 

For any mains larger than 12", an economic width of trench 
for all laying purposes, will not afford room enough on each 
side of the pipe to ensure that the space between the bottom of 
main and of trench is filled even loosely, and therefore, unless 
there is a willingness to incur extra excavating expense, it 
must be understood that there will be under all large mains a 
space of varying dimensions, which will afford a gas leak a 
fairly free passage. However, this is about all the harm done, 
with the resulting chance of making the exact location of a 
future leak somewhat harder. If the main is properly blocked, 
it will not settle, and if the trench is elsewhere properly filled, 
the hollow under the main will cause no earth settlement. 
Nevertheless, because it is impossible to entirely fill the space 
under the main, does not mean that no effort should be made 
to fill as much space as tools and trench will allow. The 
larger the main, the more attention should be paid to this first 
tamping, and the better the laborers assigned to the work. 

With a proper proportion of rammers to shovelers and the 
right kind of rammers, which mean men able to and paid to 
ram hard, there will usually be no difficulty in replacing all 
material removed for mains 8" and smaller. On larger mains, 
where earth has to be hauled away, an accurate account should 
be kept of such removed material, and if it exceeds the volume 
of the pipe laid, an explanation should be forthcoming from 
the foreman. 

In recent years power rammers, driven by gasolene or com¬ 
pressed air have become available. They are probably still in 
an experimental stage, but with the increasing difficulty of pro- 


83 


curing good labor, the value of such machines, both as labor 
saving devices and as ensuring proper ramming, will increase. 

In any refilling, but especially in ramming, care is necessary 
to protect from injury, all small pipes exposed in the trench, 
especially any lead water services. These, where over the 
pipe, should be blocked from it, or if under, from the trench 
bottom. In either case the blocking tends to prevent any 
pressure of the earth on the lead pipe, pulling it out of the 
water main. Ramming over terra cotta pipe should be care¬ 
fully done to prevent a smashing in and possible stoppage. 

If the trench is to be paved at once, refilling should stop at 
the point below the surface where the paving base begins. 
Otherwise, the trench should be filled to the street surface, or 
at the most, only slightly mounded. If it should happen for 
any reason that material is lacking, enough should be procured 
to leave the trench surface flush with the rest of the roadway. 

Occasionally in trenching, it is advisable, or necessary, to 
tunnel under certain paving or structures. These tunnels 
usually exist in connection with trenches refilled by ramming 
or puddling. Ordinarilly it is more economical to break down 
the tunnel roof, than to refill from the sides. Of course, where 
structures such as street railroad tracks, with concrete road 
bed, are concerned, breaking down is not the right course. 

PUDDLING. 

Puddling appeals to every foreman because of its cheapness, 
and should be practiced wherever the conditions are favorable, 
viz., where the soil is of the right kind, and there is no danger 
of water soaking into cellars, or undermining the pipe. 
Puddling in a street made of filled in material, may cause a 
general sinking of the street surface. In built up sections, 
puddling may be objectionable because of the chance of water 
getting into cable conduits, or because of the inability to pave 
at once upon the puddled material. 

When puddling has been decided on, the pipe should be 
covered at least six inches by well rammed earth before any 
water is let in. Also, if the trench has over 5 per cent, grade, 


8 4 


the first ramming should reduce the grade to this figure, in 
order to prevent any wash under the pipe by water sinking 
through the loose fill. Dams at frequent intervals will also 
serve to prevent any scouring out by water flowing down a 
grade, and in any case, dams would be necessary to confine the 
water to each terrace made by the first ramming. 

The preliminary ramming being done, the trench is filled to 
about one foot of the surface, and then water turned in. 
Usually the water is obtained from the nearest fire hydrant, 
hydrant keys being furnished by the municipal authorities, 
often on payment of an annual fee. Care should always be 
taken to avoid injury to paving by the flow of water over it. 
As the water flows along the ditch, bars are hand driven 
through the loose material into the rammed earth alongside 
the pipe. As the bars are driven down, they are swung 
around in a circular direction, and the funnel shaped holes so 
made allow much water to soak into the earth around the 
pipe and perhaps carry earth to fill any voids under the pipe, 
but there is no chance for a flow of water rapid enough to 
affect the stability of the pipe. As the earth sinks under the 
action of the water, more earth is added, especially when 
needed to preserve any desired channel for water flow, which 
is not stopped until the earth is well saturated and water runs 
over it without being absorbed. Then the remainder of the 
earth is thrown in and lightly rammed into a slight mound 
over the trench surface. Too much ramming is to be avoided, 
as it tends to produce a spongy condition. Too much water 
is also to be avoided, as tending to soften the bed of the 
trench, causing the pipe to settle and to make the refilled 
material so soggy as to delay repaving. Ordinary labor cannot 
be trusted unwatched on work of this nature. 

The method above described is considered preferable to the 
practice sometimes followed of throwing in all the earth and 
digging a trench in the centre of the mound for the water to 
follow. Such a procedure leaves no dry earth to finish off 
the trench. 


»s 


Where services are laid in connection with the main work, 
especial care should be given to the repair of the opening made 
in the house wall, if there is to be puddling and the water 
line will be higher than the service opening. Of course, the 
more porous the soil, the more reason for a good cement coat¬ 
ing, both on outside and inside of wall. Also, a dam of dirt 
should be thrown across every service trench at its junction 
with the main trench. 

LOOSE FILLING. 

Naturally the largest amount of main work will consist in 
extensions to the existing system, made necessary by new 
buildings and usually such extensions are laid in unpaved 
streets. With the ordinary size main and an interval of some 
months elapsing between laying and paving, there can be no 
objection to loose refilling of the trench, leaving to time and 
street traffic the gradual consolidation of the refill. In such 
unpaved streets there are always many trenches beside those 
made for gas purposes, and the roller used by the paving com¬ 
pany is relied on to compact the entire road-bed. 

The surface of this trench after a loose refill is that of a 
mound perhaps a foot high. This serves as a' warning to 
wagons to keep away. It is incumbent on the gas company 
to make a frequent enough inspection of the trench to ensure 
the prompt filling of any dangerous holes that may be formed 
after a hard rain. Also, a certain amount of trimming of 
the mounded earth may be required from time to time. 

CLEANING UP. 

The final cleaning up after any main laying job can only 
take place when repaving is complete, but as in many cases 
the repaving is done by a contractor; such cleaning up as may 
be done before repaving and by the company’s employees, will 
be treated of now. 

Almost any one can open trench and obstruct and dirty a 
street and footway. Few contractors on street work ever 
clean up properly. All gas companies should see to it that 


86 


the natural disgust induced in the occupants of any street at 
seeing it torn up is followed as quickly as possible by a feeling 
of satisfaction at the prompt execution of the work and the 
thorough restoration to conditions previously existing. A 
broom and sufficient buckets of water are aides not often 
enough used in the final stages, but they are generally needed 
to do justice to the occupants’ property in the removal of all 
earth stains on the house fronts, side walks, tree trunks and 
boxes, grass, etc. 

In this connection, good planning of a job to be sure the 
difficult portions are not neglected, will do wonders to make 
the work move along continuously and not leave any gaps 
remaining open for days after the work on each side is finished. 

REPAVING. 

GENERAL CONSIDERATIONS. 

It is not considered advisable to describe the art of paving, 
and this not only because it would add to the length of a 
treatise already very long, but also because many companies 
find it advisable to contract their paving. This tendency is 
increased by the growing prevalence of asphalt, the restora¬ 
tion of which by the company is out of the question. In the 
old days when cobble and rubble were alone met with, a few 
paving tools and a little sand were the only equipment needed 
to enable every main and service gang to restore their own 
paving. So far only roadway paving has been in mind. A 
like change has occurred in the footway. Cement has given 
place to bricks, and again the new form requires more skill 
and equipment in its restoration than did the old. Therefore, 
as has been said before, the tendency is to contract out the 
paving. This involves more lamping of trenches, rather more 
office work in connection with paving bills, and possibly more 
inspection of paving work, though with reliable contractors 
their work need not require any more attention and inspection 
than would company paving. By inspection, two results are 
obtained: No poor work is allowed to remain, as an annoy- 


37 


ance to the public and a bad advertisement for the company, 
and no dangerous holes may exist long without detection. 
As the details of an inspection system will vary greatly accord¬ 
ing to local conditions, no description of one will be given 
here. 

ASPHALT. 

If the street is a much travelled one, it is advisable to leave 
the trench in such shape that it may be driven over during the 
interval between refilling and repaving. This condition has an 
added advantage that it dispenses with the expense of lamp¬ 
ing the trench. When the material has practically all gone 
back, the concrete of the base (if any) should be thrown in 
on top of the earth, and then the asphalt pieces laid down. If 
the pieces have been well cut, a very good job can be made. 
In some cases of service trenches on important streets, with 
extra care in cutting the asphalt, and the use of a little cement 
in the cracks between the pieces, a very fine temporary job 
results. Again, the base material may be left along the trench 
or at the curb in piles and just the asphalt laid back, or the 
asphalt may be left piled up and the trench surface finished 
off with the base materials. In most cases, however, it is 
probably true that the surface of a long trench cannot eco¬ 
nomically be made safe for bicycles or motor cycles, and if 
there is much of such traffic, it would be necessary to lamp 
the trench until repaving. 

In order to ensure prompt repaving, it is advisable to pro¬ 
vide in the contract for decreased prices for all delayed work. 
Lor' instance, if paving is supposed to be laid within four days 
of receipt of notice, seven-eighths price might be paid for pav¬ 
ing laid five days after notice, three-quarters price six days, 
etc. Also, the use of concrete base under all asphalt, whether 
the original paving had such base or not, will result in a grati¬ 
fying absence of settlement, a condition always glaringly 
apparent in asphalt. 

In towns without any asphalt plant it will generally be 
satisfactory to the municipal authorities to substitute a cement 


88 


finish on a concrete base for any asphalt torn up, this being 
regarded as temporary repaving only, and being replaced on 
the first occasion that asphalt material is available. 

CONCRETE BASE PAVING. 

Most modern street paving is laid on a concrete base, and 
the tendency of this class of paving, as with asphalt, is to 
intrust its restoration to a contractor. Usually the more or 
less broken masses of concrete form the surface of the trench 
as left by the rolling gang. Whether such a trench will need 
lamping or not until repaved will depend on its location, the 
compactness of its top surface, the amount and character of 
traffic, etc. 

ALE OTHER PAVING. 

Under this head falls vitrified brick, belgiau block, cobble 
and rubble, all on sand base. Where small openings only are 
made in such paving, there are many arguments in favor of 
its restoration by the same gang that did the opening. In 
other words, on detached service or lead work, the ability of 
the gang to do its own paving will save all lamping cost, as 
well as a certain constant expense entailed by unpaved trenches, 
such as water in cellars. Also, it is possible to get better 
paving done by the company’s men than by the contractor’s. 
When opening in a street requiring sand between the paving 
stones, one of the obligations of a gas company, in order to 
ensure a good job, is to see that such sand is actually brushed 
in between the stones and not left on top to be a nuisance on 
windy days. 

As a rule, however, the fact that much of the paving is 
better contracted for, will incline the average company to 
contract for all. In doing so a bigger profit is often paid to 
the contractor than is realized, until it is found by experience 
how cheaply, with proper organization, sand base (and even 
concrete base, if there is enough of it) paving can be done. 

Below is given some information as to equipment useful in 
paving work: 


8 9 


PAVING SMALL OPENINGS AROUND STOP 
BOXES, ETC. 

i Light push cart similar to a plumber’s push cart, containing: 

I Spoon bar i Caulking hammer 

i Street broom i Pick 

i Small galvanized bucket i Sharp nose D-handle shovel 

i 6" Cold chisel i 6" Trowel 

I Stop box cleaner Cement, sand and bricks 

i Brick hammer 


PAVING SERVICE AND SMALL MAIN OPENINGS, 
i One-horse open body spring wagon, with a small top over the seat 


for the protection of the men, 

2 Street bars 
i 3'x4' Mixing board 
i Street broom 
i Dust brush 

1 Galvanized bucket 

2 Cold chisels 

I Paver’s, straight edge 
i Curb or radius edger 

1 Wooden float 

2 Brick hammers 

i Caulking hammer 

1 Concrete knife 

2 Picks and handles 

1 Pitchen tool 

2 Diamond points 

This equipment is sufficient to 
paving except asphalt. 


containing: 
i Rake 

i Belgian block or paving rammer 
I Dirt rammer 
i Dot roller for cement 
i Seamer 

i Flat nose D-handle shovel 
i Sharp nose D-handle shovel 
i Sieve 

i Finishing trowel 
i 4" Trowel 
1 8" Trowel 
1 Monkey wrench 
Paving supplies such as cement, 
brick and crushed stone, etc. 

do, on a small scale, all kinds of 


PAVING LARGE MAIN OPENINGS. 

Fdr extensive paving the number of tools listed just above is 
increased depending upon the amount of paving to be done. 


RECORDING. 

REASONS FOR RECORDS. 

A knowledge of the number of feet of each size of pipe 
comprising the street main system is valuable at all times, and 
very necessary when a valuation of the mains is required. 
7 


90 


This knowledge, subject to varying degrees of error, is 
possessed by every company, and almost always presupposes 
the possession of a map showing the location of the mains by 
sizes. In many cases, however, not only is there great un¬ 
certainty as to the correctness of the sizes shown, but also the 
location as measured from the property or the curb line, is 
either wanting or incorrect. This lack of proper records is 
often the natural consequence of the fact that in the beginning 
the location and size of every main was easily a matter of 
memory for the few employees. As the system grew and new 
employees succeeded the old, there was failure to transfer 
records from brains to paper. Another reason for lack of 
records, or improper ones, is carelessness in past years in pre¬ 
serving and entering the information furnished when the main 
was laid. 

At present the necessity for proper street main records is 
thoroughly appreciated, and the problem has been solved in 
many different ways, depending upon differences in local con¬ 
ditions and in the human equation. In what follows, will be 
found a description of methods of which experience has 
proven the worth. 

SYSTEM OF RECORDS FOR NEW MAINS. 

In determining the character of requisite street main records 
the usual condition is that of a main system sadly lacking in 
data regarding existing mains, and therefore needing records 
of maintenance as well as extension work. Before consider¬ 
ing this condition, the rarer one will be considered, where an 
entirely new main system is being installed either for a com¬ 
peting company, or for the first company in any locality. 

FIELD RECORDS. 

For the field record, that is, the one taken out on the work, 
a Transit Book is very convenient. This is 4* 4 " x 7*4", has 
about sixty leaves, and is ruled with horizontal and vertical 
lines. In making the records, a zero point may be taken at 
the beginning of the line, and all locations along the line given 


9i 


with reference to this zero. For long lines, especially in coun¬ 
try roads, this is the best way, and it is also very convenient 
in city streets. Following this method, once the proposed 
line of a main has been measured over, and the position of all 
desired points of reference noted, any portion of the main as 
laid can be quickly shown on the record, no matter whether 
gaps occur or not. 

The amount of record that will be needed to enable the main 
to be properly located on a map, and also easily found where 
occasion requires uncovering, will depend entirely upon the 
number of changes occurring in depth and alignment. The 
depth to top of pipe and the distance out from the curb, or 
property line, should be given every one hundred feet when 
there is no change, and where the dimension is changing, at 
enough points to-define the line. A single line will suffice to 
show the pipe. All special castings, whether branches or 
bends, should be accurately located, the length of each special 
being considered to be the distance between the faces of its 
bells, where it has two bell ends, or between the bell of adjoin¬ 
ing pipe or specials, when the special being measured has two 
spigot ends, or between the bell of the special and the bell of 
the adjoining pipe or special, where the special being measured 
has one bell and one spigot end. A bracket mark, “],” at 
right angles to the length of the pipe is an easy way of repre¬ 
senting the face of every bell, the horizontal lines extending 
away from the face of the bell. 

When the points of reference along the main, such as divid¬ 
ing property lines, intersecting roads or streets, etc., are not at 
right angles to the main, these points should be located by their 
intersection with whatever line is being used as a base to 
measure distances at right angles to the main; and not by their 
intersection with the main itself. 

With all specials thus located at the proper distance from 
the assumed zero point, the amount of straight pipe laid at 
any moment, may be easily calculated, and in some cases, this 
is an easier way of getting it than by adding up a series of 


92 


figures showing the work day by day. Any portion of the line, 
where the depth is changing rapidly, or where the pipe is not 
parallel to the reference line, must be measured along the pipe 
itself, and such measurement recorded and used, instead of the 
distance as measured on the reference line between the stations 
marking the beginning and end of such deviations in line and 
depth. 

When there ar£ many specials in close proximity, which 
usually means many changes in depth and alignment, the scale 
sufficing for the ordinary portions of the line will prove too 
small. Therefore, either the scale ought to be increased at 
these points to give a proper sketch, or else a detail sketch on 
a larger scale should be shown elsewhere. 

While, as a rule, the depths would indicate which way the 
line was dripping, at the same time it is surer and much more 
convenient for purposes of permanent record, to indicate the 
direction of drippage by an arrow, parallel to the line and 
pointing with the flow. 

A record of other structures encountered is generally of 
sufficient value to warrant the slight extra work so involved. 
This record of foreign structures increases in value as under¬ 
ground conditions become more congested, and when there is 
another gas company, whose records are probably not very 
complete, any records of its mains are apt to prove very useful, 
either in competition or consolidation. Where the foreign 
structures are mains, they can be indicated in the same way as 
the main being laid, though probably not in so much detail 
Where they are conduits, and therefore almost invariably 
rectangular in section, a line may be drawn indicating the 
nearest upper edge to the main being laid. This, in connection 
with the distance from the centre of the main, the breadth and 
depth of the conduit, and depth of its top surface below the 
street level, locates it completely. 

It is of value to indicate on the record the date on which 
each foot of main is laid. This is very easily done by placing 
the date of each day’s work between arrow heads, located at 


93 


the proper points. Where, for any reason, the work is quite 
discontinuous, this graphical record of dates may prove quite 




valuable as a history of progress and of work condition from 
day to day. 

Fig. 23 shows several pages of a Transit Book with a record 
made out according to the ideas above given. 

REPORTS TO OFFICE. 

Where the company is a small one no work progress report 
to the office is needed, as the information can be obtained by 













94 


an inspection of the field book, or is a matter of personal 



knowledge with the main foreman. When these conditions no 






















































95 


longer obtain, and a daily or weekly report is needed, a form as 
shown in Fig. 24, should be used, printed on a postal card 
where mailing is necessary. “Repaved” shows the total num¬ 
ber of feet repaved to date; “Back Filled,” what has been filled 
but not repaved; “Pipe Laid,” the amount of pipe laid where 
trench has not been refilled; “Trench Open,” the amount open 
in which pipe is not yet laid; “Pipe Strung,” the number of 
feet of pipe delivered on the work and not yet laid. This 
information is particularly valuable in the case of a long line, 
and gives the office a clear idea of what the physical condition 
of the work is at the time of report. 

PERMANENT RECORDS. 

The best form of permanent records for the conditions we 
have been considering all along, viz., an entirely new system, 
will depend somewhat upon the maps and their scale that are 
available for the streets occupied. For all large and many 
small cities, atlases may generally be obtained with plates 
whose scale varies from 200 to 500 feet to the inch. There 
are very few small towns for which maps are not obtainable, 
and in the country there are usually the maps of the Geological 
Survey to fall back on. No company should make up its own 
map except as a last resort, for map work easily runs into 
great expense. 

On the map a line will indicate by its color the size and gen¬ 
eral location of a main, but the scale will be too small to make 
it advisable to indicate specials, drips or any details of line. 
To get such details, a different set of records is wanted, except 
indeed in companies selling say less than fifty millions a year, 
in which the original field book record will, with the map, 
SU pply all necessary information. When the field book is 
used, the map should indicate field book number and page con¬ 
taining the record of every block, or say 500-foot section of 
main. In this way an inspection of the map shows at once 
where to go for the detailed record. 

When the field book information is transcribed, the desirable 


96 


unit for the new detailed record is either the city block, or for 
country roads for lines under 1,000 feet, the total length of 
main, and for lines over 1,000 feet, some fixed distance, such as 
500 feet. The material used for the record should be some¬ 
thing like tracing cloth, or thin bond paper, from which blue 
prints may be made to form the working file, while the originals 
themselves are kept in a fire-proof safe. Each sheet should 
be about 7" x 18", and should give the main in plan^and in 
elevation, and be a faithful transcript of the field record in 
every point necessary to give a proper idea of the location of 
the pipe and of other structures encountered. The drawing 
need not be to scale, and in this way speed may be gained and 
more space given to points on the line where many specials 
were used. Each sheet should be numbered and the various 
sheets numerically arranged in groups of one hundred. The 
general map, or maps, would in this case bear the proper record 
numbers opposite each block, or unit distance. Thus, to find 
any detailed record, it would only be necessary to look at the 
map, see the block number, and turn to the proper group of 
detailed records, where in its numerical order would be found 
the record desired. 

When there is much occasion to refer to the detailed main 
records, the above system is exceptionally valuable, because of 
the quickness with which the records may be found. Where, 
for any reason, such as for instance to locate a main for a 
service gang, it is necessary to send a record on the street, a 
convenient way is to make a rough free hand sketch on a 
white scratch pad, 5^2" x 8^", in triplicate, by means of 
carbon paper, of the location wanted, give all three the number 
of the record from which taken, send one sketch on the street, 
and file the other two numerically. The service man should 
be instructed to return the sketch, and no other sketch need 
ever be made for that particular location, until all three are 
lost, or worn out. 

Where the record may be needed on the street by the main 
foreman, there is, of course, no reason why the proper blue 


97 


print should not go out, but for service work the sketch system 
is preferable. 

SYSTEM OF RECORDS FOR NEW AND EXISTING 
MAINS. 

SMALL COMPANY. 

Coming now to the condition that confronts the average dis¬ 
tribution man, viz., a main system that is being enlarged every 
year, and that is also lacking in proper records of many exist¬ 
ing mains, two systems of records could be used, one for the 
new mains along the plan already described, and another sys¬ 
tem for the old mains, the exact location of which is unknown. 
Where the company is selling less than fifty millions annually, 
which means a small town with few underground structures 
and few specials in the main system, one of the most con¬ 
venient and easy ways to record information of old mains, as 
obtained from time to time, and to collect this information in 
a convenient shape, from which to make a graphical record 
later on, is by the use of the book, of which a specimen page 
is shown in Fig. 25. 

The book was written up for every street on which mains 
were known to be, and distances shown between each inter¬ 
secting street. As illustrated “O” is the east fence line of Erie, 
and “202” the east fence line of Huron, which is also taken as 
“O” for distances in the next block. One line of the book was 
allowed for every 25 feet, and any work done on a main, or 
information gathered by uncovering it, was entered on the 
proper line according to the location. Of course, if there were 
to be many openings, this book record would not provide 
adequate space, and therefore it is only recommended under 
the conditions already described. As will be noted, it also 
affords an opportunity for recording leaks. 

To record the new mains of the small company just con¬ 
sidered, the field book record, as described on page 96, with 
no transcribing, would be very adequate. 


9 8 


LARGE COMPANY. 

The larger the mileage of mains, the more argument there 



probably is for the use of one system of records, for both new 


Fig. 25.—Main Record Book. Page 97. 


















































99 


and old mains, although where, as is very often the case, the 
greatest amount of new mains are laid in one or two compara¬ 
tively restricted areas on the outskirts of a growing city, there 
would be no confusion resulting in one system of records for 
these new mains, and another system for all others. Going 
still further, it is quite feasible to lay all new mains according 
to the field book system, and by means of the number on the 
general main map, it could be told at once where to look for 
any particular record. The presence of a number opposite 
the block, for which the record was desired, would indicate 
that such record was made according to the field book system, 
and would be found as a blue print in the pile( or file) indi¬ 
cated by its number. The absence of a number would indicate 
that the record was on a sketch card (to be explained later 
on) and would be found in the proper alphabetical file. 

The great value of the blue print record lies in its present¬ 
ing a continuous record of the main, but it does not lend 
itself to changing conditions, and this is one of the greatest 
objections to using it in large cities, where, apparently for 
many years to come, the installation of various underground 
structures, especially wire conduits with their attendant man¬ 
holes, will cause many changes in main locations. To meet 
these conditions, the system of records used in Philadelphia, 
alike for new and for old mains, has proven very successful. 
Before describing it, a general account of the Philadelphia 
organization for obtaining records is advisable. 

SYSTEM OF RECORDS IN PHILADELPHIA. 

ORGANIZATION. 

There is a Superintendent of Records reporting directly to 
the Engineer of Distribution. Under him is a Chief Drafts¬ 
man in direct charge of obtaining, mapping and filing records, 
through the agency of street clerks and draftsmen. A street 
clerk is usually a graduate of a technical college or institute. 
Upon employment he is first put to work in the Records 
Division to familiarize himself with the system of records, one 


100 


of his duties being the duplicating of records. After this 
inside apprenticeship, he is sent out to record the work of one 
or more street main gangs. In this position he is able to 
learn all the details of street work, and to qualify for the 
position of foreman in charge of main or service work. The 
position of street clerk, besides serving as a training school 
for future foremen, superintendents and managers, allows the 
gang foreman to devote his entire time to directing his men. 
When the foreman is held responsible for his main records, 
either the records or the work, or both, are apt to suffer. 

The draftsmen in the office, post upon the main charts the 
records as made by the street clerks, and also furnish various 
reports needed in connection with main work. 

Each street clerk is provided with the following equipment: 


i 45°, 6" angle 

i 6o°, 4" angle, for field book 
1 Brass plumb bob 
1 Note book, 334 ,, x6 ,/ , 100 leaves 
1 Sketch book, 4 1 / 2 "x 7 1 / 8 ", 60 
leaves 

1 Piece of yellow chalk 
Clips and fasteners of various 
kinds 

I Chalking cord 
1 Band dater 
1 Street directory 
1 Set of ink eradicator 
1 Combination ink and pencil 
eraser 

1 Draftman’s soft pencil eraser 


1 Holder for Daily Progress 
Report 

1 Black, blue, red, brown, green 
and yellow drawing ink 
1 Set of instructions to street 
clerks 

1 Set of drawing instruments 

2 Ink pads, one red and one black 
1 3-H lead pencil 

1 Medium lead pencil 
1 6' extension rule 
1 Piece of soapstone 
1 Set of rubber stamps 
1 50' metallic tape 
Pens, blotters, printed forms 
and other stationery 


FIELD RECORDS. 

A field record is made of all openings. A standard field 
sketch is shown in Fig. 26. As all subsequent records depend 
upon the field sketch, the measurements are carefully taken 
and clearly plotted in every detail. Memory is not relied on in 
any way for information necessary for the final record. A 
3-H pencil only is used for this field work. Each sketch is 
indexed at the back of the field book, alphabetically by its 


12.0^ 


IOI 


'4 

.t 


COrvc. 3-1-13 

FINI 3 -£>-i 3 


-(copy P-KOIvA 

I .. FOKtMANS INSTROCTION) 


-€>" vV. M.„ 
■ 3 ‘- S" COV 



3 \ 


RE.IVI. 3* OP" <2j" 


^ ^ « i'-o" h'l-d' 


V-d' 

Z 1 

6= 

_ 

r-3 

Lil-^c 

1 
,— 


--' 

1 

z 


C.O'S 


5NYDLR. 






(Tn 


3 '-^. 

CO V. 


1 2 -" I DRAIN 
3 " c.i- 
UNDER 
OF <DRO.=>.S 


I 

1(0 


AVCL 


3'-z''coV. 


I 


T 



vo 

JL 



J 


Fig. 26.—Field Sketch. Page 100. 






































































102 


street name, and when the book is full it is turned into the 
office where it is dated and numbered. 

In making field sketches the following points are observed in 
connection with measurements: 

USE of measuring equipment. 

Fig. 27 shows, in a general way, the application and use of 
the tape line, measuring rule and plumb bob. The tape line 
is drawn sufficiently taut to bring it to a straight line, but is 
never stretched, and as much as possible it is protected from 
the weather. If it becomes wet or soiled, it is dried before 
winding into the case. Every two weeks each, tape is tested 
for length against a steel tape. In using the plumb bob, three 
trials are made for each measurement taken. 

measurements: how and when taken. 

Curb lines are used as bases of reference wherever possible, 
otherwise building or fence lines, car tracks, etc. All meas¬ 
urements at right angles to a main or street axis (known as 
“ordinate’’ measurements), are taken from the nearest curbs 
and measured to the centre of the main from the outside edge 
of the nearest curb. Ordinate measurements are taken at all 
angle points in the line. Ordinate measurements of foreign 
structures are always taken with reference to the centre of 
the nearest gas main, and are to the nearest edge of rectangu¬ 
lar structures and to the centre of circular structures. Ordi¬ 
nate measurements of foreign structures with reference to 
curbs are not ordinarily taken. 

All measurements parallel with a main or a street axis 
(known as “axial” measurements) are taken from the inter¬ 
section of the curb serving as a base for the ordinate measure¬ 
ments, with the intersection, actual or produced, of the nearest 
curb of the nearest intersecting street. Where streets intersect 
at angles other than right angles, measurements are taken as 
shown in Fig. 28. The intersection of the curb lines of such 
angle streets is obtained by the crossing of the two lines of 
cord extended along and in line with the curbs whose inter- 


103 



pig 27.— Measuring Equipment. Page 102. 

























104 



Fig. 28.—Measurements at Other Than Right Angles. Page 102. 






















section is desired; or by using a chalk line, the intersection 
may be found with the aid of one cord only. 

All depths are taken vertically from the top of the street 
surface to the top of all structures. Elevations are not shown 
in the field book unless the structures to be sketched are quite 
complicated, as it is thought the ordinary plan will not show 
conditions clearly. 

Axial measurements on branches are taken from the inter¬ 
section of the axes to the face of the nearest bell in all three, 
or four, directions. Axial measurements on bends are taken 
for each angle point to the face of the nearest bell, and are 
measured along the axis of the bend. Axial measurements on 
Y’s are taken from the intersection of the axes to the face of 
the nearest bell in all three directions. Bushings are counted 
as being one inch long, and caps as four inches. 

Other details that are necessary to bear in mind when taking 
field records can be stated to better advantage when describing 
how the permanent records are made. 

REPORTS TO OFFICE. 

Each day the street clerk makes a report in triplicate, one 
for the office in the district in which he is working, one for 
the Records Division and one for himself. This report is 
made on the form shown in Fig. 29. The form is self ex¬ 
planatory, except possibly as to the information called for in 
the lines opposite “Laid or Overhauled, Valve, Drip Services, 
etc.” In these cases the character of the work is indicated by 
drawing a line through the proper significant letter. 

PERMANENT RECORDS. 

From the field book record a permanent record, known as 
the “sketch record,” is made on the form shown in Fig. 30, 
whenever any pipe is laid, or old pipe uncovered, of which 
there is no satisfactory record. This form as well as Fig. 26 
is quadrille ruled, not shown by the illustration. Where only 
a few feet of old straight pipe is uncovered and no foreign 
structures, the record is made on the form shown in Fig. 31. 

8 


io6 


Wo..To.Inc. DATE . 

MAIN WORK DAILY PROGRESS REPORT 


DISTRICT 


LOCATION 

.SIDE 

SIDE 

SIDE 


INSTRUCTION NO. 





CLASSIFICATION 





SIZE MAIN 

•• 

• • 

M 

M 

COMMENCED 





TOTAL LENGTH 

» 

f 

• 

• 

DATE OF LAST REPORT 
OF INSTRUCTED JOB 





TOTAL OF LAST 

REPORT 

4 

9 

• 

• 

REPORTED TO-DAY 

• 

• 

• 

9 

TOTAL TO DATE 

TCH 

TCH 

TCH 

TCH 

LAID OR OVERHAULED 

td 

L O X 

r 

0 

SKB 

axs 

0 

L O g 

ABANDONED TO-DAY 

—OF ” 

—OF ” 

-OF " 

—OF ” 

REMOVED TO-DAY 

—OF " 

u. 

0 

1 

—OF ” 

1 

—OF •• 

VALV E, D RIP.SERV.OR 
PRESSURE TEST. STA. 

V D S P 

V D S P 

V D S P 

V DSP 

FINISHED 



1 


FOREMAN 



1 

1 


leaks:. 

REMARKS. 


REC'D R. D.ST. CLERK... 

FORM 4—P.G.W. MARK 3; ORIGINAL TO R. D., KBEP I, I TO DISTRICT. I5M-I-I7-I3. 


Fig. 29.—Progress Report. Page 105 











































































io7 


Side K \ N/l B A\_l_ St. 

IOTH TO 2y' E.E.C. st. 

Commenced 2 > — 1^5 — * 9>3 1 ^-*" 1912 > finished 3 " 13 l 9>3 

No. Inst- K°-CMssIficcdion 


fliVe cover of structures when 
it does not cross ga& mein. 

10"Dk Gi' CO'J. £- *»' 




Note. 

TAKE ALL MEASUREMENTS TO GAS 
MAINS INDEPENDENT OF OTHER STRUCTURES 
IN THE ORDER &< SEQUENCE ILLUSTRATED. 

keep abandoned pipe measurements 

INDEPENDENT. 

MEASUREMENTS to ALL OTHER 
STRUCTURES TO E>E MADE RELATIVE TO 

THE GAS MAIN MEASURtMENTS . _ 

<y..fc CoVr 


i 21-G^. \j 

-3T- f * 




PLAN 
Illustrating howa stfo&tone 
should be measured -from 
a njain. 


Fig. 30.—Sketch Record Data. Page 105. 




















































io8 


SKETCH DETAILS. 

In making the sketch record, Fig. 30, the following details 
are observed: Nothing is drawn to scale, but all of the 
structures are shown as they exist relatively to each other. 
The crossing of figures with lines and the crowding of figures, 
notes and lines are carefully avoided. The name of the street 
in which most of the work is done is given at the top of the 
form. The North Point is stamped in red in the upper left 
corner. 


MAIN RECORD. 


Nearest house No. St. 


Nature of work 

Charge 


Date 


Size Cover 

Ft. Ins. 

Drips towards 

St. 

Location of Main 

Ft. Ins. 

of 

Curb-line of 

St. 

Location of Joint 

Ft. Ins. 

of 

Curb-line of 

St. 

Kind of Joint 

Joint recaulked 

Yes 

No. 


Bell faces . 

Foreman 

Kind of paving 


Base 

Kind of soil 

Location of 

Foreign Structure 



Size 

Cover 

Remarks 





Rec'd B. of R. 

Form 33 P. G.W 

Sign here 
Make 2—1 to Bureau of Records— 

1 to Oistrict. 

10M-C-20-10 


Fig. 31.—Main Record Card. Page 105. 


In general, the ruled lines of the record card are used in 
every feasible way, and when possible, the centre lines are used 
for the mains to be sketched, which are shown by lines 1/32" 
wide, according to the following scheme: 

*Pipe laid in new work.solid red 

Existing pipe uncovered .solid black 

Pipe abandoned .solid green 

Pipe removed .broken green 

Pipe relaid .solid red overlaid by- 

broken black 

*When wrought iron pipe is used, this fact is stated. 

Foreign structures are indicated by lines 1/32" wide and the 
following scheme is used: 























io9 


Water mains .solid blue 

Conduits .solid yellow 

Manholes, handholes, sewers, inlets and 

house drains .solid brown 

A separate record is needed where manholes enclose mains. 
Where a foreign structure is being laid at the same time as a 


CHESTNUT 


ST 



: o® 

r 

lO 


pig 22. —Designation of Curbs and Corners. Page no. 


gas main, but is not actually in place when the main record 
is taken, its approximate location is shown by a dashed line 
of appropriate color. Clearances are shown in red and give 
the minimum distances between the main itself and also be¬ 
tween a bell and any foreign structure. 











no 


Curbs and corners as they exist at time of work are shown 
by a solid black line 1/32" wide, as in Fig. 32. Building and 
dimension lines, etc., are shown as in Fig. 33. Telegraph poles, 
lamp posts, fire plugs and pier lines, when needed as bases for 
location, are shown by conventional designs. Figures giving 
sizes, dimensions, covers, etc., are in black above the line in¬ 
dicating the main, the size being shown at right angles to the 
main to avoid confusion with dimension and location figures. 
Solid line rubber hand stamps are used to designate the various 


DIMENSION UNE.S -»--►* 

EXTENSION L_irSE.e>- 

PROJECTED CURB- 

PROPOSED GLJfSe*- 

BLDG. Q-i HOUSE - 

ACTUAL CORE* --— 

FENCE LINES -I-|- |- 

DRIVEWAYS - 

STAKE. L-\N»E_ -X-X-X- 


Fig. 33.—Building and Dimension Lines. Page no. 

forms of bells and specials. Reducers are shown solid, tapered 
to indicate change in size. 

When pipe or specials, are only partially exposed, the record 
indicates this. Under ordinary conditions, the street clerk 
does not leave in doubt the character of any special only 
partially uncovered, nor the relations between any intersecting 
mains. 

Where a main is carried through the air, over or under a 
bridge, detailed information of its location is given. Where a 
new bridge is being laid, a working plan is always prepared 


















Ill 


before the work is begun, and the record made by the street 
clerk serves as a check against this plan, where the work is 
carried out as originally intended, or records any difference 
between execution and plan. Where an existing main is over¬ 
hauled, and there is no satisfactory record of its location with 
relation to the bridge, the street clerk secures as detailed a 
record as may be consistent with safety. 

Where pipe is laid above ground for temporary use only, but 
such use may extend over several months, a special record is 
made. 

Where mains cross under steam railroad tracks, a plan is 
usually prepared in advance of the work, and the record as 
taken shows the relation between the tracks and the main, and 
serves as a check against the plan. In the case of street car 
tracks, a record of the tracks is not ordinarily taken where the 
main crosses at right angles, but is always taken where the 
main is under the track for some distance, as might be the case 
if the main lies parallel to the track, or crosses under switches. 

For each job, in addition to the sketch record made out 
according to the foregoing rules, all the information needed 
for the sketch record card is filled out on the reverse of this 
card, which is shown in Fig. 34. 

Of the information contained in the sketch record, there is 
transferred to the proper main chart only the size and general 
location of the main, using water colors for easily and quickly 
washing out, thereby preserving the surface of the chart. 
When these charts are on a scale no larger than 200 feet to 
the inch, it is a mistake to indicate on them any details as to 
specials except the use of fillets to denote connections. When 
the charts can be obtained on a scale of 50 feet to the inch, a 
fairly complete record may be made, but the same large scale 
that makes this detailed record possible allows such a small 
extent of territory to be shown on any one chart that experi¬ 
ence shows the charts on a smaller scale are used for ascer¬ 
taining the mains in any particular region, while the sketch 
records must usually be resorted to for certain necessary 


112 


r 0«N. 32 P. 0. W. 3M-1 2 9-m 

MAIN WORK SKETCH RECORD. 

DISTRIBUTION DEPARTMENT 

RECORDS DIVISION 


Req 

NO. 


AMOUNT 

A UT H 




Total 

PIPE 

Laid Progress Report 

Straight Pipe only 

LENGTH 


OF 

of 

of 

CEM. LEAD 


«• 

«* 

1 • 



fl • 

• 1 

«• 



1« 

* • 

< t 


Total 

Pipe 

Overhauled 




of 

«« 




1 < 

« •• 



«• , 



Plotted 

Monthly 

Mains Laid 

no. Ft. 

Recordeo 

A. 4. R. 

Bettereo Compared 

H ICHWAY 

on Chart 

Report 

Report 

Pi pe 

Mains for Notes 

SUPERVS 

no. 

DATE 



Old 

Date 

DRAFTSMAN 

DRAFTSMAN 



INITIALS 



New 

1 NITIALS 





c. I. Material Used No. 


Foreman...Caulkers . No 

..No. No. No 

REMOVED..... 

ABANDONED IN GROUND. 

JOINTS L C S . PHOTO. NO... ALBUM NO. 

Business Classification N. b .A. B. L..A. P. A. R.. i. p. 

nature of Work. 


Received, r. d 


.Street Clerk 

Per... Duplicator. 

(over) 


Fig. 34.—Sketch Record Card. Page ill 





























































details which even a scale of 50 feet to the inch cannot show, 
and therefore the limited use of such a chart does not warrant 
the expense of preparing it. 

The sketch records for the work of the current month are 
filed until the end of the month in a special file. After the 
end of the month, when the monthly work has been properly 
recorded, the sketch records are transferred to the permanent 
file, where the arrangement is alphabetical by street names, all 
records for the same street being filed by street number. In 
order to make this filing by number possible, a hypothetical 
number is assigned to every record. Where the work involves 
only a street intersection, or an intersection and more or less 
work beyond the intersection in the direction in which the 
street is numbered, the hypothetical number assigned is the 
highest number belonging to the intersection on the proper 
side of the street. Where the work does not involve an inter¬ 
section, or, if involving an intersection, extends beyond it in 
the opposite direction to the numbering, the number assigned 
is the lowest one belonging to any building, or lot, on the same 
side of the street as the work, and in front of which the work 
is done. 

When a record embraces in part, or entirely, the same extent 
of main covered by a previous record, it is filed behind the 
earlier record. Where mains are frequently changed, it often 
happens that a true idea of the exact main location in any one 
block, or at any one intersection, can only be obtained by 
reference notes and by spreading out several sketch records 
made at various times, and noticing carefully how the later 
records make partial changes in the earlier ones. In this way 
the very state of affairs, viz., great activity in the installation 
of underground structures, that renders advisable the adoption 
of the sketch record system, as opposed to the “blue print” 
record, previously described, because of the greater ease with 
which small changes may be shown by means of the sketch 
record, sometimes produces so many sketch records relating 
to one block, or intersection, that it becomes advisable to make 


H4 


what is called a “composite” record. This shows in one 
record, the block, or intersection, as it is at the time of making 
the record, and until the future brings new changes, the com¬ 
posite record is the only one that is consulted. 

BRIDGE MAINS. 

REASONS FOR BRIDGE MAINS. 

Until recent years there were no bridges in territories pro¬ 
vided with gas mains, except where such territory was divided 
by a body of water. In many instances, the stream spanned 
was navigable, and the resultant draw-bridge was of no use as 
a pipe support. Where the bridge was a fixed one, or where 
the approaches to a draw-bridge extended over a long stretch 
of land, marshy or otherwise unfavorable for main laying, in 
the former case, the whole bridge, and in the latter, the 
approaches, have been welcomed as a means of facilitating the 
conveyance of gas across the water. 

With the growing abolition of grade crossings of steam rail¬ 
roads, within the limits of towns and cities, has come a great 
increase in bridges, of which a respectable proportion carry the 
street over the railroad. If it is necessary or desirable to 
convey gas across the railroad at any one of these bridges, the 
choice lies between crossing on the bridge, or laying under the 
tracks. The latter alternative is usually undesirable for sev¬ 
eral reasons, of which the two principal ones are as follows: 
First, the objection of the railroad company, which desires to 
reduce to a minimum any work by outside persons, in any way 
affecting the roadbed. If the right of way at the point of 
crossing is owned in fee simple, permission to cross will be 
given only on condition of removal on specified notice. This, 
of course, is not a condition that the gas company cares to 
accept. In every case the railroad must be held harmless for 
any damage resulting from the installation or presence of the 
main; second, the increased expense of installation and main¬ 
tenance. As a rule, a crossing under the tracks will mean a 
long stretch of deep main on each side of the bridge, or else 


two vertical legs, each about twenty feet, either underground 
back of the abutment walls, or exposed on the side (usually) 
of these walls. Invariably the amount of pipe used and its 
depth will be greater than if the location is upon the bridge. 

From what has already been said, it will be seen that the 
choice will generally be for the bridge crossing, whether over 
land obstacles, principally railroads, or over water. The dis¬ 
advantages connected with a bridge main will be considered as 
the subject is developed. 

LOCATION OF MAINS. 

When installing a bridge main, the first point to be con¬ 
sidered, viz., the necessary permission, is often inter-related 
with the second, the location. Bridges are generally owned by 
the public authorities, but sometimes the railroad is joint 
owner. Unless the addition of extra weight is considered 
dangerous, permission to lay is seldom refused, but the public 
authorities are often very much opposed to any location where 
the main will be in evidence. Generally such a prohibition 
means a location below the floor line, and entails extra expense 
in installation and in maintenance, and occasionally where the 
bridge is over railroad tracks, and the head room is limited, 
the railroad company interposes with the provision that this 
head room be not decreased in any way by the proposed main. 
The exact point at which any prescribed location becomes so 
disadvantageous as to prevent the bridge main altogether, will, 
of course, depend entirely upon local conditions. There are, 
however, some general principles as to location which apply 
universally. 

Where the main girders carrying the bridge, also separate 
the roadway from the footway, a location on the top of such a 
girder is ideal. Next in point of desirability, would be on the 
bridge floor itself, in a corner of the roadway or (preferably) 
the footway. Blocks of concave top, fitting the main, should 
raise it one inch above girder, or floor, and a guard timber 
should protect a roadway floor main. 


ii6 


If there is no location available above the floor line and 
within the bridge lines, laying along side of the bridge is 
usually preferable to laying underneath it. Often by attaching 
brackets to the outside girder, the main can be laid just outside 
the footway railing, with the bottom of the main about the floor 
level. If the girder carrying the footway, is deemed too light 
for additional weight, attachment may be made to the girder at 
the side of the roadway. This will bring the main under the 
footway. 

There may be instances where the only possible location is 
under the main floor of the bridge. At the present time, most 
of the new metal bridges crossing over railroads are protected 
over their whole bottom from the action of the locomotive 
gases by a tight wooden sheathing. Only as a very last resort 
should a pipe be laid in between such sheathing and the bridge 
floor. So laid, it will at all times be most inaccessible for 
examination and painting, will be exposed to many corroding 
influences and escaping gas will be both hard to detect and a 
great source of danger, forming as it will an explosive mixture 
inside the sheathing. Where there is no sheathing the choice 
of location under the bridge will be determined by givng proper 
consideration to the various elements of first cost, maintenance 
cost, etc., that may enter into the case. 

Where the location is under the bridge, provision should be 
made at time of installation, for a future means of ready in¬ 
spection. This generally means building a platform under the 
pipe7 or leaving hangers in which boards may readily be slipped 
at any time. 

So far the types of bridges in mind have been those com¬ 
posed mainly of metal or wood. The advent of re-inforced 
concrete has brought the concrete arch bridge into the field. 
With it, location above the bridge floor, or along the bridge 
sides, is usually prohibited on the score of spoiling the artistic 
effect. Location under the bridge in the few cases where head 
room was sufficient, would mean a small stretch of main ex¬ 
posed in an inaccessible place, with most of the pipe buried in 


the sides of the bridge arch. This location also pre-supposes the 
laying of the pipe while the bridge is being built, for it is not 
probable that permission would be given to tear apart any 
existing bridge. In most cases, there should be no hesitation 
in letting the pipe be entirely built into the bridge, its location 
being usually as low as allowable without exposure on the 
underside of the arch, in order to avoid contact with the cinder 
base of the bridge surface. If a leak should develop at a pipe 
joint there is little chance of gas finding a way out through the 
concrete. In fact, in a concrete bridge, it is well worth con¬ 
sidering where the length is great and the saving would be 
considerable, whether a cylindrical passage formed in the con¬ 
crete would not suffice. 

PROVISIONS FOR MAINS WHEN DESIGNING 
BRIDGE. 

Except in discussing the concrete bridge, no distinction has 
been made between a bridge that has been built without any 
reference to the need for laying mains on it, and a bridge de¬ 
signed after ascertaining what necessary provision should be 
made for pipe crossings. There is little excuse for any com¬ 
pany that allows the erection of a bridge, on which there is a, 
present, or possible future need for a main, without making an 
attempt to have the location of the main previously settled. 
Probably in all large cities the official in charge of bridge work 
notifies the company of each bridge planned and asks them 
to state their needs as to pipe crossings, and to consult with him 
as to location. In any locality in default of such notice, it is 
very easy to have a knowledge of all proposed bridges. 

Where the main location is to be alongside, or under, the 
bridge, the work of laying can be greatly cheapened by suitable 
openings left in any masonry, and sometimes by holes drilled 
in, or brackets fastened to a girder, before it is put in place. 
A good plan in regard to the openings in masonry, is to have 
the specifications state that the contractor will place thimbles at 
places designated by the plan, these thimbles to be furnished by 


n 8 


the company. In this way the company is bound to know 
where the thimbles are to be placed, and their cost is in¬ 
significant, consisting as they usually do of spigot pieces of cast 
iron pipe of a size just large enough to permit the insertion of 
the bell of the size of pipe being laid. 

DESIGN OF MAINS. 

MATERIAL. 

Ordinary cast iron pipe with lead joints will probably need 
frequent re-caulking, due to vibration of wood or metal 
bridges, and also to temperature changes in exposed pipe. With 
cement joints in sizes 12" or under, vibration would probably 
not cause leaks, but temperature changes probably would, and 
in larger sizes,both vibration and temperatures might be sources 
of trouble. Where cast iron is buried in a concrete bridge, it 
is perfectly satisfactory, but the thickness of the bridge at the 
arch crown may be so slight that the lesser diameter of a 
wrought iron joint, as compared with a cast iron bell, makes 
wrought iron pipe preferable for the concrete bridge, as it cer¬ 
tainly is for the wood, or metal bridge. On the latter, the 
saving in space and weight afforded by wrought iron is quite 
desirable. Also, in the case of under floor locations, the fewer 
joints and lessened chances for leaks are important points. 

JOINTS. 

RUBBER. 

For mains 6 ", or under, in size, the ordinary form of 
screw coupling is advisable. For 8 " possibly, and for 12" 
and over certainly, a rubber or asbestos joint with plain end 
pipe should be used. As compared with screw pipe, there will 
be a saving in first cost (always in labor and often in material) 
and in maintenance, for, as each joint acts as an expansion 
joint, temperature changes bring no strain on the line, and 
there should be no leaks. 

SCREW. 

Where screw joints are used, an expansion joint of some 
kind is advisable, one for one hundred feet of exposed 


pipe. Where there is only one expansion joint, it should be 
located in the centre of the line; where more than one, they 
should be equally spaced. 

Each expansion joint should be firmly secured to the bridge, 
in order to prevent any chance of one joint taking up all the 
movement. At the ends of the line, where the wrought iron 
joins the cast iron, (usually just before the main goes under¬ 
ground) it is often easy so to locate the necessary specials, 
that any thrust or pull will be taken up by a swing joint effect. 

SIZE. 

The size of the bridge main is ordinarily that of the under¬ 
ground main on either side. However, in cold climates, it is 
probably a mistake to lay smaller than 4", and in many cases, 
smaller than 6". Also, if the region supplied is a growing one, 
or of large extent, the bridge main should be large enough to 
care for future growth, especially if the location is such that 
replacement would be difficult. 

The above applies where the main is of moderate size, say 
12" and under. Above 12", it might often be true that the size 
of the main very largely added to the expense of the job. If 
this is the case, it will often prove good practice to make the 
bridge main smaller than the pipe to which it connects. To 
what extent this diminution in size is advisable, will depend 
upon the special conditions in each case, one of the important 
factors being the length of the bridge, and another the demand 
for gas during the peak load. 

One way of avoiding the use of very large pipe on a bridge, 
when the size in itself is the objection, is by laying two or more 
mains. A case in mind is where a concrete arch bridge was 
built over a single track steam railroad, well in advance of any 
development on the street which the bridge served, or in the 
general neighborhood. Future plans for the locality called for 
a 20" main on the street. When the city authorities asked what 
provisions should be made for a gas main, it was soon found 
that the minimum depth over the arch would not permit of 


120 


larger than a 12" wrought iron pipe. Neither could permission 
be obtained to lay alongside or on top of the bridge. To go 
under the railroad was not advisable. Therefore, the decision 
made was to bury two 12" wrought iron pipes side by side in 
the concrete of the bridge. They, of course, will not give the 
capacity of a 20", but the bridge is less than 80 feet in length, 
and the day when the 20" capacity may be needed is so far 
ahead, that a third 12" pipe did not seem justified. 

Except where required for real, or assumed, artistic rea¬ 
sons, because of protection from gases of combustion, or be¬ 
cause of severe cold, it is not advisable to enclose the main, but 
instead it should be painted with red lead, covered with a quiet 
color. A wrought iron pipe kept well painted is bound to be 
less conspicuous and take less room, than the same pipe boxed. 
A cast iron pipe with its large bells does not present a neat 
appearance. A box around the main on the floor, or side, of 
a bridge is a great collector of dirt, and corrosion will progress 
faster on a main covered by the ordinary box than if bare. 
Any covering over the pipe also renders any inspection much 
more difficult, and any escape of gas more dangerous. How¬ 
ever, there are cases where at least a wooden shield under the 
main, to protect it from the direct impact of the gases from 
locomotive or'boat stacks, is quite necessary. 

As to the question of protection from cold, in the old days' 
when a 6" was a large main, a time honored rule was to make 
the pipe rising out of the ground, and going over the bridge at 
least a size larger than the underground pipe. In these days 
of large mains, it is safe to say that no such practice need be 
followed for latitudes south of New York City. In Philadel¬ 
phia, the few cases of exposed mains stopped by frost have 
been confined to 3" pipe. Where the climate is severe enough 
to warrant the enlarging of pipe, then also the question of pro¬ 
tecting all exposed pipe needs to be considered. Whatever 
form of covering is adopted, great care should be exercised to 
make it water-tight, not only to keep the insulating efficiency 
high, but also to prevent corrosion. A good quality of canvas, 


121 


kept well painted, will especially, when space is limited, form 
an excellent water-proof cover. 

INSPECTION OF MAINS. 

All bridge mains being more liable than the underground 
piping to injury from atmospheric and other external causes, 
should receive a periodical and careful inspection for condition, 
in addition to the prefunctory inspection given to them by the 
line-walker from time to time. This careful inspection should 
be at least yearly, and a good time is during the fall months, to 
ensure that everything will be all right for winter. The in¬ 
spection will usually disclose the necessity for repainting, for 
minor repairs to platforms and coverings, and in the case of 
cast iron pipe may mean a resetting of many of the joints. 
Where pipe is exposed to the action of combustion gases, it is 
also well to attempt to form an idea of how fast corrosion 
may be proceeding. A 12" cast iron pipe exposed under a 
bridge crossing many busy railroad tracks, was found on re¬ 
moval to have in many places less than *4" of metal left. 








